I agree, all in all we aren't talking about 2 girls smitten with the same guy situation which can possibily ruin their friendship: one of those doesn't care (yet) and the best other one is only starting to trust him, so I see no conflict here.
One thing is sure though, if you wanna be with either Jill or Bella you have to make sure the latter likes you first ("If you don't get along with me, you won't get along with her. I can assure you that").
Now we know Bella gave up on male gender or she simply thinks guys of that age are still immature ("I know boys like you. You're only after one thing"), but, especially if you play the Chick route, you realize that the MC is the good, romantic guy who cares about family and love; in other words, he's the perfect guy who can change Bella's mind (and hopefully make her happy again).