To better understand confidence let's first clear up some really common misconceptions between confidence and self esteem. The two are related but are not the same. Confidence is how effective a person feels in a given situation or dealing with specific task. Self esteem is how much a person likes themselves and how worthy they feel of receiving good things in life. A person can feel good about themselves (high self esteem) while not feeling positive about there chance / skill-set in a certain area (confidence). This can also happen in reverse.
Self Esteem VS Confidence
Lets take an example and relate it to pickup. Say a guy has great game and knows he can get any girl in the bar (confidence) this is separate from how he feels about himself overall (self esteem). In reverse a guy might have very high self esteem but have lously game and when he gets into hard sets (hotter girls, shit / congruence tests, unexpected social patterns, amogs, etc) he will display signs of lack of confidence though his self worth remains unaffected.
Where does confidence come from? Well many factors generate / affect a persons confidence level. Some of these might be there previous expereiences, there performance, how they feel they meet up to the standard and the feedback they are getting.
Here's where it gets interesting though... a person's self esteem can directly affect confidence. How a person feels about himself (self worth) can directly correlate to how he will do a in a new situation. This is why Inner Game TRUMPS Outer Game. You might not be use to models or strippers or whatever your 10 is. If you very strongly outer game based there will be a point where you are out of lines, routines, tactics, etc. At that point what will you do. A common mistake guys make is they stop being the guy that attracted her in the first place. Once you run out of routines it is like the social robots post by style.
Conversely if you are strongly inner game based you will just be that really chill guy, sure you might not have the right response, or line, or whatever but the vibe you put out will be so much more powerful and effective then having that right line. I always thought one of my biggest sticking points was that i was not scripted enough. I tell people this on every bootcamp and every 1 on 1. I believe this but I believe the reason I am successful is because I love myself. There are things i hate about myself (my teeth, my posture, etc) but I am working on them and I am work in progress. My strong inner game allows me to be in situations where maybe I dont have the right tactic but just my vibe and positivity is enough for to make it through the rain (to gayly quote mariah carey).
Now here is somethign else that is interesting. The opposite of what I said two paragraphs ago is NOT true. A person who places a strong emphasis on confident feelings (looking good, acting alpha,) may look this way to someone who is not in the know. However a person's self esteem are really affected by there execution of free will and not the clothes he wears or the car he drives. What you may see as high self esteem is really just him gratifying his own inflated ego.
In conclusion, self esteem and confidence are both psychological fores at work but the way they influence and impact the pysche are different yet similar. Almost like kissing cousins
Hope this helps someone