Rosalie hates Bella primarily because of jealousy and resentment rooted in her own tragic past. Rosalie envies Bella's humanity and the choices Bella can make—something Rosalie lost when she was forcibly turned into a vampire. She is frustrated that Bella wants to throw away her human life by becoming a vampire, something Rosalie herself would give anything to reverse. Additionally, Rosalie feels jealousy because Edward desires Bella, not her, despite Rosalie's beauty. Rosalie also fears Bella's involvement with Edward might bring problems to the Cullen family. This complex mix of envy, regret, and protectiveness explains Rosalie's hostile attitude toward Bella in the "Twilight" series.
