The problem you have is you seem to think that you can figure it out by thinking about it, by getting some amazing insight or some realization from someone else or through sheer willpower and then viola you get it. You now have the all important confidence you lacked and you can get girls left and right. If it was something you could get by thinking about it a lot of nerds would be getting laid cause they spend a disproportionate amount of mental effort thinking of getting girls compared to actually attempting to get girls. i don't know how much effort you've put in but you probably need alot more effort than others and when a guy gives you advice it will take X amount of time, he's giving you based on his ability to reach a reasonable proficiency level.
I could tell you it took me a few weeks of struggling while doing a certain system like David De Angelo's and its true to get it, but I was a social person with other attributes which made it easier for me to get it faster. The only way to become confident is through going out and making friends (male and female) and becoming a social being, become a C&F person, become whatever it is you think will bring you success by continually thinking and acting in line with whatever you choose. If your confident you'll still feel nervous sadly, but you'll still make the approach and whether it goes well or not you realize there's another girl in close proximity whose attractive and could like you, and if none of the girls in an entire mall like you there's still millions more. Hey, your friends like you and love hanging out with you, you have girls who fall for you and people think highly of you or whatever. You have a wealth of positive references that act as a foundation so that even when you fail and there's no one on your side you know you have the ability to make more friends, meet more girls, build a new life easily cause you've done it before. You might not have those things now but if you think a certain way (negatively) and feed yourself positive affirmations it'll never work.
If you make an effort everyday to think positively and back it up with positive action, start with small things and move up to bigger tasks not necessarily starting with your weakness girls. That mentality will affect the way you view things over time if you persist. The little things add up to the bigger picture, I don't know why you think you can feed yourself some bull affirmations and suddenly they work when you've been thinking a different way your whole life. That kind of programming can't be defeated overnight. Women ain't going anywhere if you take the time to work on your mentality, posture, building friendships, breaking bad habits, working out, better clothes, just aiming to be someone who enjoys life and has a solid foundation it'll help in more ways than you can imagine.
Start speaking in front of a mirror and watching how you speak, if you have a presentation try and defeat your fear of speaking in front of others, speak up when your in a crowd. I've personally done most of these and I'm glad I never ask questions about how to become confident or faking confidence. It's like asking how to fake being a doctor when you don't have the qualifications, you don't have the foundation of experience. It's not an accurate example but you get the idea cause some people naturally get it RIGHT? Not really! Those naturals practice through exposure to women in some form and gained an understanding of them and even if they fail, they get success and success is a great stimuli to keep doing the things that work while someone who never tried or who expects a couple months work to help when they were never social. They get discouraged when they see others who started way before them getting success and the negative cycle doesn't add to their success, it keeps them desperate and bitter at their lack of success, a recipe for... well, failure.
You get my point. Don't just attempt to get women, work on yourself mentally, spiritually and explore EVERY avenue. If you get discouraged a positive mentality will work wonders compared to a defeatist attitude. Whining you'll never get it. When I get rejected I'm damn glad I made the approach than sit there wondering what if. You ever tried playing a game like pool while being scared your gonna lose, you know what happens? You lose! When you think you can't lose, you usually win and even if you lose you'll win the next one.
