The personal  perception 
of a one's own value as a human being.
Most people have an
inaccurate self-image and that tends to contribute to a low
self-esteem more so than an inappropriately inflated
ego,
IMHO.
You can't give someone self worth.
If I could give everyone in the world just one thing, it wouldn't be flowers or something Miss-America-like, it would be self worth.
If everyone had that, we wouldn't have a lot of the problems we do today.