I think Jacob likes Bella so much because if আপনি are a boy and আপনি have a friend that's a girl আপনি will start to notice that আপনি have feelings for her. That's only if আপনি two have been বন্ধু for a long time.
It's not really something which can be explained. People don't exactly choose to প্রণয় someone else. Some অনুরাগী 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.
