well, and you can gain that type of confidence observing a little of body language.
Have you ever noticed if a guy was attracted/interested in you?.
Like a guy you don't know, glancing at you more than once. Or looking at you deep in the eyes. Or fixing his clothes or whatever after seeing you.
Or biting his lips or so... Then he is somewhat interested in you, at least from a "looks" point of view, that's doesn't mean much in the end, but at least you will see there would be no problem because of your looks with that guy. That doesn't mean you could have a date or so but that he likes your looks.
I don't know much the body language of men when they like a woman but viceversa, but it must be something like this.