If I'm not interested in her then I'm fine. As with talking to anyone I just get a little anxious and I'm a hopeless conversationalist.
When I used to be interested in a girl, I would avoid talking to them, because if I did, I was an absolute mess.
These days, I instantly tell myself that she won't be interested, she has a boyfriend, or she's out of my league, and there's no point in pursuing her, to avoid rejection. So I've just learned eliminate the feelings and treat her as any other person.
Of course, this means I'll never show interest in a girl. Though at least I can actually talk to her comfortably, meaning she is able to show interest - providing hell freezes over.
For the record, I have had no history with girls at all, because of lack of self confidence and because I know I am a hopeless depressed loser. Like you, I long to be loved, but to avoid disappointment, I'm in the mindset that I'll be alone forever.