This is my own ideas on how the miller's daughter turned into the Cora we know today. None of the characters are mine of course.
There was once a poor miller who lived only with his young and beautiful daughter in a kingdom ruled by a greedy king. The miller drank so much, he hardly ever worked, so day by day the two had less and less to call their own. The young girl, confused by how her mother ever loved such a man, swore she would leave one day, but never fall in love or get married. The miller was not only a drunk , but also a fool who never thought before he spoke. One day, while the king was out hunting, the miller stumbled to him and bragged about how his daughter could spin straw into gold. King George was skeptical at first, but everyone knew he had a weakness for gold, so he rode to the miller's house and had the daughter brought to his castle.
Once she found out why she was there, she pleaded with the young king to believe her father was a drunk and didn't know what he was saying, but George ignored her, thinking she wanted to keep her gift to herself. So the young girl was locked in a room with a large pile of straw, and the king told her if she didn't turn it into gold by morning, she would die.
"Please, I'm begging you! I can't do this, it's impossible. Why do you need so much gold?" she pleaded.
The king only shook his head and spoke in a sad tone. "I know my people are suffering, with this much gold, they won't have to go hungry. Now finish your task."
He marched out and locked the door. The girl sat down next to the straw, with only the few things she packed in her satchel, and tried to think of a way out. She understood the king thought he was doing what was best for his people, but he would be disappointed in the morning. With no hope left, the young girl began to cry.
Soon after, she heard a shrill laugh and looked up to see a strange man in front of her. He was wearing expensive clothes, but his skin almost looked reptilian. Angered by his laughter, the girl glared at him and asked him what he wanted.
"Oh, it's not what I want dearie, it's what I can give." He answered in riddles, but the girl had no other choice but tell him her problem. "Well you are in luck!" he exclaimed with a wide grin, "for I can do such a task!"
The girl wiped her tears and gave him a small smile. "You will help me?"
The hope in her voice left as he wagged his finger at her. "I am the Dark One, I only do such things for a price."
The girl frowned, for she had nothing to give. But then she remembered her ring, so she took it off her finger and handed it to him. "Will this do?"
The Dark One examined it, then gave her another crooked smile. "Yes, yes this will do child. Such a unique ring, this stone, is it in the shape of a heart?"
The girl smiled, remembering the story of how her mother named her after her favorite ring, then gave it to her when she was just a girl. "Yes, it's for my name, Cora."