Please allow me to translate your letter into "man language" for those among my readers who don't speak fluent "pussy."
WAAAAAAH! A girl wants my hot bod, but I'm too big of a fucking faggot to care! She won't stop trying to jump on my cock!
Heh, ok, fine, I'll be serious. And in all seriousness, what's wrong with this girl? Is she ugly? Bad breath? A flat ass/chest? What, might I ask, makes her so unworthy of your magnanimous affection? I have never had a platonic female friend that I wouldn't have at least considered being more serious with (unless you count kids, but I suspect you're not talking about an 11yo here). I don't know any man who has. The only reason I can think of that a guy wouldn't want to at least give it a shot is because there's something wrong with her. So don't try to pass me that plate of bullshit about "I just wanna be friends." No, it's not that you have some lofty moral conviction against fucking your friends, it's that you don't wanna be with her, specifically, for whatever reason. That's fine. Nothing wrong with that, but let's be honest about it and not have this bullshit.
The first thing you need to consider is the possibility that you might be wrong. She could just consider you a really close friend and want to spend time with you as really close friends. Has she told you, flat-out, "I want to be more than friends" or something similiar, but equally as direct and leaving no room for doubt? No she hasn't, which means that you could be making a giant ass out of yourself by ignoring her and shit when maybe she just enjoys your companionship as a friend.
Think about what kind of person she is. If she's hanging around you so much and wanting more and more of your time, it could simply be that you're the only friend she has (or maybe just the only "true friend"). Maybe she's jealous of your other friends. Ever consider that, asshole? No, of course you haven't. You're too busy thinking that this poor girl actually wants your herpes-ridden cock. If you brought this up to her directly, she might just go "WTF? Are you kidding me?!"
But, that's only one possibility. It is also likely that you're right and she wants your Jimmy Dean Premium Sausage to make its home in her taco salad. If that's the case....
Well, really, it doesn't matter which scenario is true. My advice is the same for both. I favor the direct approach. Ask her, point blank, "Are you interested in me?" I mean, if you're so sure that she is, then you shouldn't have any worries about her responding "LOL, you n00b! You phail @ teh mind reedng!" So just be straight with her. Nobody likes to be jerked around and if she really does have feelings for you that she is making abudantly clear to you, then you're being a real dick and stringing her along, whether you intend to or not. As long as she has hope, you will never be free of her various stalking behaviors and will always live with the horrible haunting fear that you will awaken one morning to find your dick in her mouth after she climbs in your window at 3am.
Of course, you should be gentle. Gentle, but direct. Don't piss around the rim, buddy, aim for the bowl! Give her the old "I value you as a friend / You're like a sister to me" speech. That'll work. Well, I mean, it won't keep her from being hurt. Far too late for that now. If she's interested in you, she's gonna be hurt and that's just the way it is. That's not your fault, it's her's. You're just being honest. She's the one who was dumb enough to make her feelings plain as day.
Again, a word of caution though. Since she hasn't explicitly told you that she has romantic feelings for you, then maybe you should assume that she doesn't! She could just as easily be lonely and want more of your time as a friend. Don't make an ass out of yourself and hurt her unneccesarily.
Wishing You Diseases,