Introduce other positive elements. For instance, the enchanted objects from the Beast's castle could come to Belle's aid in a non - violent and magical way. This way, the story doesn't get too dark. Also, you can end the story on a positive note, like Belle escaping and Gaston learning a valuable lesson, rather than having a very tragic or overly violent ending.
Focus on Belle's strength. Even when tied up, she can be shown as mentally strong. For example, she can be thinking of escape plans or ways to outsmart Gaston. Also, don't go into too much detail about the tying - up part. Keep it more about the situation and the characters' reactions rather than the act itself.
One plot could be that Belle's friends come to her rescue just in time. They could outwit Gaston using their unique skills. For example, if the Beast was also involved in the fanfiction, he could use his strength and knowledge of the forest to find Belle. Another plot might be that Belle manages to free herself through her own wits. She could trick Gaston into loosening her bonds by pretending to be scared and then making a sudden move.
It could be that Gaston ties up Kairi and Belle out of jealousy. He's jealous of the attention they receive from others. In the story, while they are tied up, they could recall their own past experiences of facing difficulties. Kairi might think about her adventures with Sora and how she overcame challenges. Belle could think of the time she tamed the Beast. This reminiscing could give them the strength and motivation to break free. They might start by trying to call for help in a way that only their friends would understand, like a special whistle or a call that has a hidden meaning. Then, when their friends arrive, they could all join forces to deal with Gaston.
Sora could be the one to save them. Since Kairi is important to Sora, he would sense that she is in danger. He would use his keyblade skills to fight off Gaston and free Kairi and Belle. Sora is known for his bravery and determination, and he would not let Gaston get away with such a malicious act.
Belle would likely be cautious at first. Even though Gaston is tied up, she knows his strength and his unpredictable nature. She might use this time to try and reason with him, to get him to understand that his pursuit of her was wrong and that there are more important things in life than just physical appearance and power.
The story would take a whole new turn if Gaston and Belle were in a relationship. Gaston, being the way he is, would likely try to mold Belle into the 'perfect wife' according to his standards at first. But Belle, with her strong will, would resist. This could lead to a lot of conflict between them. On the other hand, if Gaston truly changed for Belle, the village might see a different side of him too. However, the Beast would be left in despair, and the magical elements of the story would be disrupted. The story would no longer be about the Beauty and the Beast's journey of love and self - discovery, but rather about Gaston and Belle's struggle to understand each other and make their relationship work in a very different social context.
Belle would initially be in shock when Gaston kidnaps her. But then, her determination would kick in. She would try to keep her wits about her. Since she loves books and stories, she might draw on the knowledge she has gained from them. For example, if she was held in a cellar, she could think of ways heroes in the stories escaped from similar situations. She would also be defiant towards Gaston. She would not give in to his demands and would constantly remind him that what he is doing is immoral. And she would keep hope alive that someone, like the Beast or her father, would come to her rescue.
First, focus on the character's growth through the experience of abuse. For example, Naruto could face some form of mild abuse like being bullied at the ninja academy but then use it as motivation to become stronger. Second, add some light - hearted elements. Maybe Naruto has some friends who always cheer him up even in tough times. Third, end the story on a positive note, like Naruto overcomes the abuse and builds a better ninja world.
You can focus on the recovery aspect. For example, if a character has been through physical abuse, instead of dwelling too much on the violent parts, write about how they start to heal, the support they get from their friends or family. Maybe they find a new hobby that helps them regain their confidence.
For Gaston, you could develop his character by showing his vulnerability. Maybe he has a fear of being alone forever, which is why he's so desperate to marry Belle. With Dark Belle, you could explore her darker side more. For example, she could have a temper that she usually keeps in check. You can also have them influence each other. Gaston could make Dark Belle more assertive in a different way, and Dark Belle could make Gaston more introspective.
Belle and Gaston's meeting in fanfiction can be quite diverse. It could be that they bump into each other in the forest and Gaston immediately takes a liking to Belle's beauty, while she's unimpressed. Or perhaps they cross paths at the local tavern and have a heated exchange of words.