well, i kind of misread that. but again, i need to dissent. after ALL that up there, i kind of forgot to mention the one thing.
women are often REALLY slow investors into relationships--myself very much so. if she is completely turning you down and shutting the door, then fine, leave her alone. but please don't assume that her (apparent) lack of mutual interest is going to be always like that.
my favorite analogy of men/women "investment" is the swimming pool. guys seem to dive in, and there they are (which we just love about you, guys!). in the pool. more often, women seem to inch in from the shallow end, and some of us move at a glacial pace--because we're needing more information to proceed, figuring stuff out, etc. you can help that by opening up more, showing us different sides, and making a concerted effort to show us how you think and feel. moody (unpredictable) guys can make this so much worse.
if i am spending time with someone, it's because i think something could come of it. but honestly, i ALWAYS feel like i'm playing catch up, emotionally and interest-wise towards the beginning. some women just need time for these feelings to develop and mature into real interest. but that's how real feelings grow.
if you care for her, allow her receptiveness to be your guide, not her outward display, validation or communication of feelings. by the way, some women have no clue about this gender disparity of interest, and they will only notice that they don't like you as much as you like them, "oh noes!" especially if they're young or kind of new to the relationship thing.
and if you really don't care that much about her, well, absolutely -- put those boundaries up, cut bait and don't bother finding out what might be. love should be more than a passing fancy. decide for yourself whether she's worth your time and pursuit and the risks associated.
love is for the courageous. : )