the frog king is a sadomasochist

I’ve been reading Grimms fairy tales, looking for another story to translate. Often the plots are nonsensical or they're simplistic—as in the good guy wins. There are three brothers, the three trips to the river, the three attempts to fell a tree… Contemporary readers like to cut to the chase. We already know that only the third time counts. Who cares about the two losers? Did the 19th century truly revel in this kind of suspense?
I chose a nonsensical story. The Frog King or Iron Heinrich. Note that many English versions translate Heinrich as Henry. Heinrich is a perfectly good name that gives us a sense of the man’s cultural background. In real life I don’t call Dmitri Jimmy or Mehnaz Minnie, so why would I translate Heinrich as Henry? In French versions he gets called Henri.

“The Frog King or Iron Heinrich”
Once upon a time, when wishes were still granted, there lived a king whose daughters…
(Sorry, back up here. This opening leads you to believe that this story is about the granting of wishes. It’s not. Didn’t these books, written in the 1800s, have editors?)
Once upon a time there lived a king whose daughters were all beautiful, but the youngest was so beautiful that the sun itself marvelled when it shone on her face. Near the king’s castle lay a huge forest, and in the forest, under a linden tree, was a stone well.
(The story doesn't specify that it's a stone well, but what do modern readers understand by a well? So I'm telling you that this well is round with a stone wall with a rim wide enough that the king's daughter could sit on it. I know all this because I have the advantage of an illustration.)
When the day was hot, the king’s youngest daughter walked into the forest and sat by the cool well. To pass the time, she played with her favourite toy, a gold ball she threw into the air and caught again.
One day, as she was playing, she missed the gold ball and it dropped to the ground and rolled into the well. She watched the ball sink until it disappeared. The well was so deep that she couldn’t see the bottom. She began to cry and lament, ever louder. Then she heard a voice: “What’s wrong, Princess? The way you’re carrying on, a stone would feel sorry.”
(I’m not interpreting here. The original is familiar. “Du schreist ja…” I think this is unusual for the time, matching the voice of a character to his supposed social station. Try to find that in Austen where even the shady characters articulate with finesse.)
The princess looked around and saw a frog sticking its thick ugly head out of the water.
“Oh,” she said, “it’s you, you old water-splasher. I’m crying because my gold ball fell into the well.”
“So be quiet and stop crying. I can help, but what will you give me if I return your toy?”
“Anything you want, dear frog. My clothes, my pearls, my precious stones, and even the gold crown I wear.”
“Your clothes, your pearls, your precious stones, and even the gold crown don’t interest me. But if you will love me and keep me by you as your friend and companion, and let me sit next to you at the table, eat from your gold plate, and sleep in your bed—if you’ll promise me that—then I’ll go down into the well and get your ball.”
“Yes! I promise whatever you ask!” Though she thought, What stupid notions has that frog dreamt up? He sits in the water with other frogs and croaks. How can he be my friend?
(I can’t get a fix on the king's daughter's age. In the illustration she’s got breasts, but she amuses herself by  playing with a ball. The word the frog uses for companion is “spielkamarad”—like a play date. She’s alternately called the king’s daughter and a child. And yet, at the end of the story…)
When the frog heard her promise, he dipped his head and sank into the water. After a while he swam back up with the ball in his mouth and dropped it in the grass. The king’s daughter was ecstatic to see her beautiful toy again. She grabbed it and leapt away. “Wait!” the frog called. “Take me with you. I can’t run as fast as you.” But what did croaking help? She didn’t listen. She hurried home and soon forgot the frog who had to hop back to his well.
The next day, when the king’s daughter sat at the table with the king and all the courtiers, eating off her gold plate, there came—plitch platch, plitch platch—something crawling up the marble steps. At the top it knocked on the door and called, “Princess, the youngest, open up for me!”

She ran to find out who called, but when she opened the door and saw the frog, she banged it shut again and rushed back to the table, frightened. The king saw that her heart was beating hard.
(This is almost impossible, assuming that she’s dressed—even wearing the décolleté dresses princesses wear—but fairytales have this cartoonish element.)
“My child,” the king said. “Why are you afraid? Is there a giant out there who wants to snatch you away?”
“Not a giant. A disgusting frog.”
“What does the frog want from you?”
“Oh, dear father, yesterday when I was in the forest by the well my gold ball fell in the water. And since I was crying, the frog fetched it for me, and in exchange I promised that he could be my friend. But I didn’t think he could get out of the water. Now he’s outside and he wants in.”
Again there was knocking at the door.
“Princess, Princess, open up!
Don’t you remember your promise
In the dark woods by the cool well?
Princess, Princess, open up!"
The king said, “You know you have to keep your promises. Go open the door.”
(You might wonder that royalty is so principled when it comes to hobnobbing with a frog. But obviously the frog is more than a frog, which you already know because this is a fairytale—and now you know that the king knows as well.)
She went and opened the door and the frog hopped in, following her feet to the chair. From the floor he called, “Lift me up to sit with you.” She hesitated until the king ordered her. She put him on a chair but he wanted to be next to her on the table. Once there, he said, “Now shove your little gold plate closer so we can eat together.” She did it, though she didn’t want to. The frog enjoyed the food, but every small bite stuck in her throat. Then he said, “I’m full now and I’m sleepy. Bring me to your bedroom and turn down the silk sheets so we can lie down to sleep.”
(Don’t assume that since Grimm’s are for children, there’s no sexual connotation. In quite a few of these fairytales people go to sleep only to have a child in the next paragraph.)
The king’s daughter began to cry because she didn’t want to touch the cold frog, much less have him next to her in her clean pretty bed. The king grew angry and said, “He, who helped you when you were in need, should not be repaid with scorn.”
She pinched the frog with two fingers, carried him upstairs and dropped him in a corner. Once she was in bed, he crept across the floor and said, “I’m tired. I want to sleep too. Lift me up or I’ll tell your father.” Indignant now, she grabbed the frog and threw him as hard as she could against the wall. “There, get your rest, you disgusting frog!”
As he fell, he changed from a frog into a young king with beautiful friendly eyes. He was the beloved companion and spouse her father had chosen for her, but a wicked witch had cast a spell on him. No one could free him but herself. Tomorrow they would go to his kingdom together.
(Now. I ask you. If this man/frog was your friend, would you advise him to continue in this projected relationship? Admittedly, he’s no longer a frog. But she’s clearly bad news. She used him when it suited her purposes then spurned him. There’s that niggly issue of not respecting her promises. Why is he looking at her with “beautiful friendly eyes”? She’s not someone I’d want as a friend, much less a companion and wife. If he marries her, he’ll be plitching-platching after her for the rest of his life, whether he’s a king or a frog.)
They fell asleep, and the next morning, as the sun woke them, a carriage with eight white horses appeared. Each horse had ostrich feathers on its head and was harnessed with gold chains. Behind the horses stood the young king’s valet, loyal Heinrich. Loyal Heinrich had been so upset when his master was turned into a frog that he had three iron bands fastened around his chest to keep his heart from shattering with the pain and the sadness.
(Heinrich and his king are a well-matched pair in their penchant for punishment. One makes friendly eyes when he gets thrown against the wall; the other straps iron ribs around his chest.)
Loyal Heinrich handed the young couple into the carriage and climbed on the back seat, his heart filled with happiness for the king’s deliverance.
The carriage travelled only a short while when the king heard a crack behind him. He turned around and called, “Heinrich, the carriage is breaking.”
“No, Master, not the carriage.
The band on my heart
Which lay in great pain
As you sat in the well
When you were a frog.”
Again there was crack and then another. Every time the king believed the carriage was breaking, but it was only the bands around loyal Heinrich’s chest, because his heart was so happy.
THE END

I’m not sure what purpose the Heinrich add-on serves in this story, except as a parallel to emphasize that loyalty—as in the princess being forced to honour her promise—is iron-clad. Heinrich’s name changes from iron Heinrich in the title to loyal Heinrich in the story.
But if this story is about loyalty, then why is loyalty so badly served? The young king ends up with a bride who has a temper and no sense of honour. Not that he’s any better. His valet has bound his chest in iron bands that burst with happiness now that the king is released from the spell. Yet the king would sooner believe the carriage is breaking. Loyal Heinrich doesn’t even get a thank you for his act of homage.
Re: my translations of Grimm’s. I don’t pretend that they’re word for word exact. However, I try to honour the tone and content of the story. After I translated this, I looked at some other versions. I was puzzled by one that had the characters talking in thee’s and thou’s. “When thou werst in need.” There’s no call for this. The Grimm’s brothers were contemporaries of Jane Austen, not Shakespeare.