Self-confidence is only an umbrella term for a lot of things. Emotional constraint, humor, empathy, resilience, string relationships, all go into creating the personality that exudes self-confidence.
A self-confident person would know how to say things that are honest without hurting other’s sentiments. A self-confident man also knows how to be heard with dignity, when there is a difference of opinion. All this takes practice, but the most important thing is the belief that you can be better. This is the cornerstone for any improvement in the world.