If I was you I’d bite the bullet and ask her outright. If you don’t want to do that, then I’d look for the following:
she doesn’t call you
she doesn’t answer when you call
she is busy when you suggest getting together
she cancels plans at the last moment, and she cancels often
she just doesn’t show up
basically she is avoiding you if those things are happening, and I’d expect that she doesn’t want to be with you. If she doesn’t want to be with you, as upsetting as that may be initially, I suspect that you wouldn’t want to be with someone who couldn’t or wouldn’t be honest with you in the first place.