Well, in some fanfictions, it could be a test or trial set up by a powerful magical being. Hermione, being known for her courage and knowledge, was chosen as the subject. They tied her up and 'beat' her in a sense that was more of a test of her mental and magical strength. Or it could be a revenge plot by a student or wizard she had outsmarted in the past, who wanted to teach her a lesson.
One possible reason could be that she was captured by some dark wizards who oppose her and her friends' actions. They might see her as a threat due to her intelligence and magical abilities. Another reason could be related to a misdirected spell or curse. Maybe someone was aiming for another target but accidentally hit Hermione and then tied her up to prevent her from seeking help immediately.
One possible reason could be a misunderstanding. Maybe Fleur misinterprets Hermione's actions as a threat to something or someone she cares about. So, she restrains Hermione to prevent her from causing further 'harm' until she can figure out what's really going on.
One possible plot could be that there is some sort of misunderstanding. Fleur believes Hermione is in danger from some dark magic or a dangerous creature and ties her to the bed to keep her safe. As the story unfolds, they realize the miscommunication and work together to solve the real issue at hand. However, this is a rather strange starting point for a plot and would need a lot of careful development to make it a believable and engaging fanfiction.
One possible plotline could be a rescue scenario. Maybe her friends discover she's in this state and they have to outwit the captors. For example, Harry could use his invisibility cloak to get close and free her.
It could be a case of miscommunication. Fleur misinterprets something Hermione said or did, and in a fit of rage or confusion, she ties Hermione to the bed. As the story progresses, they clear up the misunderstanding and end up becoming friends or allies.
Fleur could be a bit hesitant at first, not fully understanding the situation. But once she realizes the gravity of Hermione's state, she becomes determined. She might call for help from other reliable wizards or witches she knows. Fleur would also comfort Hermione, telling her that she's safe now and that they will find the culprits. She may use her Veela charm in a subdued way to soothe Hermione's distress.
Well, it could develop into a story of deep friendship. Maybe Fleur was trying to comfort Hermione during a difficult time. They might start sharing their secrets and fears, and through this physical closeness, a strong bond of sisterhood could form.
One possibility could be a situation where Fleur is under the influence of a dark spell. Maybe she's been hexed to do this to Hermione. In the fanfiction world, this could be a lead - up to a rescue mission by Harry and Ron. They would have to figure out how to break the spell on Fleur and free Hermione.
I'm not aware of such a specific fanfiction. Fanfiction can cover a wide range of themes and scenarios, but this one seems rather unusual and perhaps not in line with the general spirit of the original works. However, the world of fanfiction is vast, and there could potentially be something out there that I haven't come across.
One possible reason could be envy. Maybe Fleur sees Hermione's intelligence and skills and feels threatened. So she becomes possessive to try and keep Hermione in a certain place or relationship where she can control her influence. Another reason might be that Fleur has some deep - seated insecurities. Hermione is well - liked and respected in the wizarding world, and Fleur, perhaps unconsciously, wants to claim Hermione as 'hers' to boost her own status. It could also be a case of misinterpreting friendship for something more possessive. If they are friends in the fanfic, Fleur might not know how to handle her strong feelings for Hermione in a healthy way and ends up being possessive.
They might have a very competitive relationship. Since both are strong - willed and talented. They could compete in things like magical duels or academic achievements. However, this competition could also strengthen their bond as they push each other to be better. And in times of danger, they would put aside their differences and protect each other like true sisters.