Confidence is no big deal, it comes from practising something often and becoming more skilled at it, the more someone paints, the more confident as a painter they become, the more someone trains as a martial artist, the more confident in martial arts they become and so on and so on. Now I think the original post was in relation to confidence with the opposite sex, and this is slightly different, but women just want a man who isn't INTIMIDATED by a woman and her sexuality, see Men are terrified of women but even more terrified to admit it, a woman holds a tremendous power over a man, she makes the decision who she sleeps with and who she doesn't, she can easily reject an admiring suitor and crush him into nothing, she can easily ridicule his love making, his genitals and his ego.
A woman can easily manipulate other men to punish the men who displease her. For all a man's strength and independence, his power is nothing compared to a woman's, and women know this, and that's why women want a man who isn't afraid of them, a man who will stand up to them and not act like a son does with his mother, he must stand firm against a women when the need arises and not allow himself to be dominated, to be pussy whipped or too compliant. Women want a man who isn't afraid to be himself. Essentially a man will have to overcome his fear and not be afraid in general, even though men depend a lot on women for certain needs, a woman still wants a man who will protect her from harm should the need arise.