If you're not the type of guy she would like attention from in the first place, no amount of confidence will compensate for it. "Confidence" is a nebulous catch all women fall back on when they don't want to seem shallow by calling you ugly.
Other men will shit on you as well if you're confident and ugly. See pic rel. They don't like seeing another man who they deem lesser going after what they feel is rightly theirs by birthright.