For what it is worth, I don’t think you are forced into dating her - you are forced into being friends with her - and maybe that puts her in the friend zone where she is hoping for more. But if you choose not follow up on any of the opportunities the game does not think you are dating her - because at the end where you are asked to choose which girl(s), JILL is not an option.I love this game, but I think this is one of its weak parts. We should have had the option to tell her.
I just think she is a rather fragile person and being dumped or not getting the guy she has feelings for (especially when he is with her best friend) is too much for her and she has to take time out.
The situation is created because BELLA and JILL are best friends. So if you play distant/cold/nasty with JILL then BELLA will not accept you, so if you want BELLA you have to be friends with JILL which forces the jealousy scenarios.