In fanfiction, there are no real limits to how the characters can be re - imagined. It's possible that the writer made the Cullens act in a way that is completely opposite to how they are in the original story. This change in their behavior or character traits might be the reason Bella hates them in that particular fanfiction.
It could be that the fanfiction writer took a different approach to the story. In some fanfictions, the Cullens could be involved in situations that go against what Bella stands for. Perhaps they are written to be more secretive and untrustworthy, leading to Bella's hatred.
Well, it could be that the plotlines in the Sam fanfiction are just not to Bella's taste. She might prefer different types of stories, and the ones about Sam are often full of elements she doesn't like, such as certain relationships or events that are depicted in the fanfiction.
Her relationship with Jacob would likely change. Since she hates the Cullens, she might turn more towards Jacob for support. They could become closer as she sees Jacob as an alternative to the Cullen world. With her human friends, she might try to distance herself from any connection to the Cullens. So, she could be more secretive or withdrawn from them as well to avoid any talk about the Cullens.
In some fanfictions, the Cullens might hate Bella because of jealousy. Maybe other vampires are jealous of the attention she gets from Edward. Another reason could be that she brings too much danger to their family. Her presence could attract unwanted attention from other vampires or vampire hunters, which puts the Cullens at risk.
In some fanfiction, Bella might not forgive the Cullens because of a perceived betrayal. For example, if they hid something crucial from her again. It could also be due to them putting her in danger without her consent. Another reason could be a broken promise related to her transformation or her relationship with Edward.
She might start by giving them the silent treatment. Just ignoring them completely when they try to talk to her, which would be a very human way of showing anger.
One possible reason could be that she discovers some dark secrets about the Cullens. Maybe she finds out they have been lying to her about their true nature in a more malicious way than in the original story. Another reason might be that she feels threatened by their vampire powers. If they accidentally or purposefully use their powers around her in a menacing way, it could make her feel scared and turn that fear into hatred.
Bella's character development in this fanfiction might be seen in her emotional growth. Initially, she might be a bit naive and overly curious about the Cullens. But as she grows up with them, she becomes more understanding and empathetic towards their situation. She may also learn to control her emotions better, especially when it comes to the dangerous aspects of the vampire world. For instance, instead of panicking all the time, she starts to think rationally and find solutions. Moreover, her relationships with the Cullens shape her into a more complex and well - rounded character. Her bond with Edward might deepen in new ways, and her friendships with the other Cullens could also influence her values and behavior.
Well, at first, the Cullens might be more suspicious of Bella since she's related to James. But as they get to know her better, they might see that she's different from her brother.
In the original Twilight story, Bella is initially attracted to the Cullens, especially Edward. But in this fanfiction where she starts to hate them, it's a complete contrast. It shows a different side of Bella's character, one that is more critical and less forgiving. In the original, she is more likely to overlook their flaws because of her love for Edward. Here, she focuses on the negative aspects.
Well, it could be due to the way the Cullens interact with the other people in Forks. If Bella notices that they are being manipulative or using their powers in a way that she doesn't like to influence the townspeople, that could make her start to hate them. Also, if there is some kind of power struggle within the Cullen family that starts to affect Bella negatively, like she gets caught in the middle of it or she sees how it's causing harm to those she cares about, she might turn against them.