What you're describing is but a temporary ego boost. Confidence must come from within; it should not be affected by external forces.
"Fake it till you make it" works for developing outer game and social skills, but alone won't help you develop true inner confidence. Inner confidence comes when you stop being outcome dependent and just learn to ACCEPT things.
My advice for building confidence has nothing to do with pickup; it's about learning to undue all the damage past failures have done to your ego and reverting to a state of almost childlike freedom from ego.
A good start is to focus on developing a skill you already have--it could be golf, computer programming, music, writing--really, take anything that you're interested in. Focus on developing this skill until you can reasonably be concerned something of an authority. Then--the important part--begin teaching this skill to others. You don't need to organize your own classes, just mentor some people. Get used to the idea of being an authority figure and a leader. You will notice by being forced to teach, you are concurrently developing better communication skills. People with solid communication and public speaking skills are generally confident people--this is why so many people fear public speaking!!
Doing charity work and giving back to your community also works to build true confidence because it again places you in the role of a leader. Your perspective on your place on this Earth really changes when you start helping people in need, and things that were big deals in the past (like approaching women) suddenly don't matter to you anymore.
There are some that advocate dressing ridiculously and humiliating yourself publicly in order to develop self confidence, but I find those methods to do more harm than good because of the amount of negative reactions you receive. You want your attitude to say: "This is me. I am a leader," rather than "I don't give an F*** about anything, F*** you all." It's just unnecessary and counterproductive.
Soon, you'll get used to taking the lead on EVERYTHING, whether it's making plans or tough decisions, or opening and hooking sets. Then, it's just a matter of learning to accept the outcomes without getting hurt.
Oddly enough, I got over that just by thinking a lot about death. It seems morbid at first, but the idea is to replace all the bad thoughts and dread you have about death with acceptance and trust. If religion helps you in this respect, so be it. Even if you're not religious, you can learn to accept death by realizing that it is a natural part of the life cycle, and is really just associated with peacefulness. By learning to accept my own mortality, it freed me up from regretting things in my everyday life and allowed me to accept things for what they were. I don't know if this method will work for everyone, but I thought I'd share it.
Once you have developed true inner confidence, the world is your oyster. You will start really LIVING life the way it is meant to be lived, and you actually will find it very difficult to DISLIKE other people, even if they wrong you. You start to see the lack of confidence in others manifested in ways that ultimately will harm them the most. You feel bad for girls that reject you rudely, because you realize that a truly confident person would not behave in that manner.
It's a bit of a journey, and, depending on how insecure you are to begin with, may take some time, but your life will not truly begin until you are a confident man.