Bella may become a more adventurous character. Maybe she decides to try new things that she was always too afraid to do before because Edward was so overprotective. She could start going to parties, trying extreme sports, or exploring new hobbies. This new adventurous side of her would make her a more well - rounded character, and when Edward returns, he would see a completely different Bella.
Perhaps Bella could start exploring her artistic side more. She begins painting and writing, using it as an outlet for her emotions. As she delves deeper into her creativity, she attracts the attention of a local artist community. Edward, who has been away, hears about her newfound fame in the art world and returns out of curiosity. Bella, now independent and self - assured, has to decide if she still wants Edward in her life.
Bella's character might become more confident. Without Edward, she has to rely on herself, which forces her to grow. As a vampire, she'll be more physically capable, and this could translate into mental strength as well.
Well, in many Twilight fanfics, if Edward leaves Bella, she often goes through a deep emotional turmoil. She might become very sad at first, feeling a sense of abandonment. She could also be angry, feeling betrayed by Edward. And she might become more withdrawn, isolating herself from her friends and family as she tries to deal with the pain of his departure.
In some fanfictions, if Edward leaves Bella, she might become stronger and more independent. She could focus on her own life, perhaps pursue her studies or hobbies more intently. For example, she might finally decide to travel the world and discover new things on her own.
Bella might become more rebellious at first. The idea of being forced into a marriage goes against her independent spirit. So she could start to act out, be more outspoken, and challenge the authority that is forcing her into this situation.
For Bella, show her growing strength as she faces single motherhood. Let her be determined yet vulnerable at times. For Edward, explore his reasons for leaving in depth, like maybe he was forced by some external threat. Show his inner turmoil.
Their relationship often deepens. With the idea of having a baby, they become more connected on an even deeper emotional level. They start to see each other in new roles, as future parents.
Edward would probably be very confused at first. He would try to understand why Bella would leave him for Rosalie. He might start to analyze all their past interactions, looking for signs that he missed. Eventually, he could become angry, not at Bella directly, but at the situation. He might also feel a sense of betrayal, not just from Bella but also from Rosalie in a way, since Rosalie is 'taking' Bella away from him.
Bella might start as a typical Malfoy, proud and a bit haughty. But as she interacts with Harry, she could start to see the world from a different perspective. For instance, she may notice how Harry values friendship and loyalty over blood status. This could make her more empathetic towards others outside of the pure - blood circle.
Bella could become more independent. With Paul leaving, she has no choice but to rely on herself. She might become more assertive in making decisions for herself and her unborn child.