Perhaps in the fanfiction, there's a new role she has to play. For example, if she's joining a secret society or a group with a specific aesthetic, she needs to dye her hair to fit in. It could also be a form of self - expression. She has some pent - up emotions or a new side of her personality that she wants to show through her hair color change.
One reason could be for a disguise. Maybe she's on the run from some bad guys in the fanfiction world and changing her hair color helps her blend in better.
Maybe he wants to rebel against his family's traditional image. In the wizarding world, the Malfoy family has a certain 'pure - blood' and proper image. Dyeing his hair could be a way for Draco to show his individuality and break free from the constraints his family has put on him.
Maybe he wants to change his look to disguise himself from his enemies. In fanfiction, there could be all sorts of threats and he might think a new hair color would help him blend in or not be recognized so easily.
Well, one reason could be a new start. Maybe she wants to break free from her old self. In some fanfictions, she might cut her hair after a big event like a break - up or a change in her life situation. It could also be a symbol of her growing independence, showing that she's not the same girl she used to be.
In fanfiction, it could be related to a magical accident. Maybe a spell went wrong and changed the color of his hair, and then he decided to keep it and even dye it a different color on purpose. It could also be a part of a transformation arc, where changing his appearance, starting with his hair, is a symbol of his growth and change as a character.
One possible reason could be a symbol of a new beginning. Maybe she's had a major life change, like starting a new chapter in her relationship or in her studies at Hogwarts. It could also be a sign of rebellion against the traditional image others have of her. In some fanfictions, she might cut her hair to fit in with a different group or to show that she's breaking free from her old self.
Green hair dye was a trendy hair color choice. There were many different green hair colors to choose from, such as mint green, peacock green, matcha green, dark green, and so on. These green hair colors could show different styles and personalities, from the noble and pure emerald green to the fashionable peacock green, which could bring different visual effects. In addition, green hair dye could also be chosen according to one's skin color and preferences, such as low-key and gentle green tea, avocado green, grass green, and so on. For boys, dyeing their hair green could show their personality and fashion sense. In general, green hair dye was a popular hair color choice. You could choose a green hair color that suited your personal preference and style.
If it's a hair tie given to her by a friend, it could strengthen their bond. For instance, if it was from Angela, it would be a symbol of their friendship. Whenever Bella looks at it, she's reminded of their good times together, and it might make her more likely to reach out to Angela when she's having a problem, thus deepening their relationship.
Perhaps she is forced to turn off her emotions in the fanfiction. For example, if there is some sort of dark magic or a powerful entity that compels her to do so. This entity might see her emotions as a weakness or a threat and manipulates her into shutting them down.
One possible reason could be that the Cullens make a decision about her future without consulting her. For example, if they decide she should leave Forks for her own safety without asking her how she feels about it.
Another reason could be her relationships. If she has a fight with a friend or a love interest. Let's say she and Edward had an argument over his over - protectiveness. That could easily make her lose her cool.