Dating has always been strange, it's not just these days.
Sometimes a girl can like you as a person, but have zero interest in you as a lover. It just happens sometimes, because girls don't think the way we do. They have more options and more responsibilities when it comes to this sex stuff, so they can't think like we do.
Chris Rock said it best: Guys don't have female platonic friends, we just have women we haven't f**ked yet. That's because guys are designed and built to want to have sex with every female who isn't direct family, and we can't turn it off. The need for sex-sex-more-sex was written into our DNA before we were even born, because it's a survival-of-the-species thing.
Women are wired differently. They were all designed and built to deal with the aftermath of sex (pregnancy, childbirth, feeding the baby, etc.), so they have to be more picky about who they do it with. Any woman knows she can have sex with any man she wants any time she wants, even the ugly girls know this, so they can afford to pick and choose. When someone can afford to pick and choose AND has to deal with the aftermath of sex, they're definitely not going to take the first offer that comes along.
If you had literally hundreds of women competing to have sex with you, if you could have any woman you wanted just by saying yes, wouldn't you hold out for the best of the bunch? Be honest when you answer.
I know, right? You'd nail them all! And that's exactly why men aren't in charge of who gets to have sex with who. If we were, our species would have gone extinct due to overpopulation thousands of years ago.