I think Jacob likes Bella so much because if 당신 are a boy and 당신 have a friend that's a girl 당신 will start to notice that 당신 have feelings for her. That's only if 당신 two have been 프렌즈 for a long time.
It's not really something which can be explained. People don't exactly choose to 사랑 someone else. Some 팬 theorise that he was drawn to her because she was related to his future imprint though, similarly to how Sam dated Leah before imprinting on her cousin.
