I don't own OUAT
Hard labor gave one plenty of time to think. And she certainly had a lot to think about as she looked back on a lifetime of hurting people and an afterlife to consider her regrets. She would have liked to say that, given the chance, she would have done it all differently. But then, she didn't like to lie to herself. Cora had never been what you might call a good person, and her ambition always seemed to have the last word. If she had never tricked Rumpelstiltskin, never removed her heart, she would have simply found someone else to use for power. It was just her way.
It was what she had done upon entering the Underworld. Find the person in power; make a deal… whatever it took to get her what she wanted. It was easy to find and keep power so long as she enforced Hades's rules. The rules were hardly difficult to follow, trapping everyone in the in-between place, preventing them from moving on properly. She hardly wanted to see where she would end up when she was put to judgment, so she maintained the status quo and lived a relatively luxurious afterlife.
She hardly knew anyone in the dismal place, so trapping them was far from a hardship. Henry was there, of course. It had taken over a year to convince him that she had not forced Regina to kill him, but eventually he had understood. If she had wanted him dead, there were certainly enough opportunities for her to do it herself. They kept their distance for the most part, but she occasionally sent gifts his way, always certain to make them seem natural. He was delighted when the first of his many beloved dogs had shown up at his doorstep, and she doubted he would ever question where it had come from. He had been a good enough husband, and she felt she owed him something for giving her Regina and taking care of her when she could not. So she provided for him when she could and gave him the space he needed.
It was a very comfortable arrangement until Hades had come to inform her that Regina had entered the Underworld with a band of foolish heroes on some sort of quest. He threatened to simply kill and torture Regina if she didn't solve the problem, so she did what she had to do. It was an unfortunate circumstance, and she hardly liked the threat that she was forced to make, but it would have been worth it if it had succeeded. She could have bought herself more time, more power, in order to prepare for the time at which her daughter would return for good. Then, Regina would need her, and she would provide everything that she could. But Regina had inherited her stubbornness, and the repercussions were certainly unpleasant. All she could do was hope that her daughter was able to take care of herself now.
Cora did what she had to do, biding her time until she could change the circumstances. The work wasn't entirely voluntary, but she had stopped truly fighting against the compulsion to do as Hades commanded. She expected that this must be what it felt like for those she had controlled through their hearts in life. She did as she was ordered, with a touch of freedom in respect to how it was done. There were guards, of course, and the compulsion was strong, but she had found that fighting back only served to humiliate her more, often forcing her to her knees. She refused to truly return to who she ha once been, instead playing the part of vulnerable, hopeless miller's daughter while her mind, the mind of a queen, raced. She gave in just enough for the work to be mindless, letting her thoughts drift to her past and her present, potential escape plans and things she wished to one day make up for.
It was while her mind was adrift that an opportunity appeared. She found the hook, glinting in the dimly lit cavern as she went about the meaningless work she was tasked with. There was limited time to act before the compulsion would stop her, so she quickly cut off the cuff which had suspended her magic and kept her dominated by Hades's will. Her power rushed back into her as the cuff fell off, and she let a smile take hold of her face, her first truly free action. She was only too happy to use that power to throw her guards to the side, clearing her path to freedom.
Her suspicions, of course, had been confirmed as she escaped the little cave, stopping short at his calm demeanor and "Hello, love." Hook had been the subject of more than a few thoughts while she toiled away at her work. They had had a fling of sorts, mostly composed of her using him for her own pleasure, forcing him to satisfy her when the stress or boredom became too much. He had been rewarded for his service, of course, but feelings had never been a part of it. But as she saw him, her knight in black leather and eyeliner, her magicless, rash fairy godmother, she felt a twinge of longing for something more.
They left to help Regina, but she couldn't stop the selfishness which had taken control just before they reached the outside world. She had thrown him into the cave wall, cutting off his chuckle with a kiss and silencing him before he could say she hadn't changed a bit. She let her hands explore him and proved how very different she had become by asking him how she could please him, putting his needs before her own. They were quick, but she was sure that he knew exactly how grateful she was for his rescue.
They parted ways soon after, but her thoughts returned to him as she stood before the fires of judgment. She noted with a touch of satisfaction that all of her unfinished business had been completed, between him and her girls. No one was more surprised than her to find that she had been judged favorably, but she wondered as she entered the light if somehow redeeming herself to him had helped to tip the scales.
It was impossible to say for sure, but she knew there was no better day in her life or afterlife than the one years later when he entered her little corner of heaven with a "Hello, love. I'm home."