Women are very good at sensing whether a man has self-confidence or not. And no matter how good you are at faking confidence, their better at seeing past your bullshit. You can paint yourself yellow with fake confidence all day, but you cannot glow unless it's genuine. And it's not necessarily just about good looks (though good-looking guys often draw confidence from their looks, which in turn get them girls) or just how a guy acts around you (though "assholes" do tend to get a lot of women because they act aggressively based on confidence, even if it's silly/foolish).
So then the old nice guy catch-22 comes up: I need confidence to get the girl, but I need to get the girl to get confidence. 8(
I think with a lot women, if they can tell that a guy isn't confident but notice that he's working on himself in ways that could help build his confidence, then they will still go for this. If you don't have confidence, have momentum. Be working to change your current situation to one where you can better excel, better be proud of what you are doing and be more comfortable in your own skin. You need to at least have hope, determination and drive.