Actually, I agree to pianoguy to a certain degree about how one perceives himself/herself. If you feel attractive you will become more attractive given that you put yourself out there and make an effort to find a good mate. Just thinking and knowing you're attractive will not help whatsoever.
I can say I'm so beautiful and know it, but if Im not putting myself out there no one will notice it.
If I feel ugly and unattractive, yes, I will not find a mate because people can feel that you have no confidence and yes, they will find you "ugly". Affirmations can be very strong.