Bella can be developed by showing her resilience. For example, she could start as a meek character but gradually grow stronger in the face of abuse. She might learn self - defense or find her voice to stand up against the abuser.
To develop Bella in this fanfiction, her emotional journey can be explored in depth. She could be shown to have complex emotions like fear, anger, and also a glimmer of hope. Maybe she starts to plot her escape or tries to find allies within the story world. Her relationships with other characters, aside from the abuser, can also be a key part of her development. For instance, she could form a strong bond with a friend who helps her see her own value and gives her the courage to change her situation. This could all be part of making her a more multi - dimensional character.