<human>: Can you condense the text into three sentences or less?

Okay so, i met this girl a couple times, started crushing on her, got a job with her, then started talking to her. At first we were both fresh out of a relationship/not looking to date. We started fucking, and because i don't have the ability to fuck a girl and forget about her, i started falling for her. We had that "just sex-noties relationship for about 8 months, in which time i didn't sleep with/talk to any other girls. I did try going back to an exgirlfriend, but i just couldn't do it. I can't get this girl out of my head, which made me realize she's the one. She had a foursome/fucked some other kids during the "not dating" period which i have no problem with, i'm just concerned i kind of forced her into this relationship.  Now onto my question.
She thinks she's not good enough for me. I think i'm not good enough for her at all. How am i suppose to change the way she feels about this? I want nothing more then to treat this girl better then any guy ever has, which i've told her plenty of times before, it just seems like she either doesn't believe me, or doesn't want it. How can i get her to be completely straight up with me? What if she is lying to me to protect me from getting hurt? I'm very self-concious and i feel like because of this she's just going along with the relationship because she doesn't want to hurt me. I know posting this on the internet isn't going to solve my problem, i'm just hoping someone has some advice on what i can do to figure out if she's really in it for the long haul with me. On top of that. I keep telling her all the insecurities i have in hopes to talk it out etc, i just feel like it's either annoying her, or making her want this relationship less then she already possibly does.
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<bot>: I think i'm annoying my girlfriend with all my insecurities. How do i know if she's 100% with me or just fucking around without hurting her feelings.](/bold)