Lack of belief?

For the longest time, I've been the "hopeless romantic" type; I always wanted to believe there was a girl out there for me. I'd hoped I'd start dating in high school, like everyone else. When that never happened, I was a little disappointed, but I knew that was okay. When I was starting college, I'd hoped I'd find a nice girl to get closer to, but after four years, that still hasn't happened.

I've only REALLY been interested in a girl one time, but nothing ever came of it; not that I didn't try, she just wasn't into me. Ever since then, I... I dunno, I think I just stopped believing that there's someone out there for me. I don't know why. I mean, yeah, I was kind of hung up on that one girl for a while, but I'm over that whole thing by now. I just can't picture myself being in a relationship anymore, for some reason. It just no longer seems realistic for me. Not that it ever did before, but back then, I was at least hopeful, and it didn't seem so "out there". Now, I'm at a point where it seems so crazy unrealistic for me.

I guess what I'm wondering is, is it possible to "believe" again? If so, would it even be worth it? I want to believe, but thus far, all it's ever brought me were sadness and loneliness.