I see self esteem as importantly related to self confidence, but these two as also importantly different. One can have a good deal of self confidence in the various abilities one has to succeed in the various aspects of one's life, and yet lack significantly in self esteem.
I see self esteem as something which can be eroded by negative self-talk ("I'm just not good/worthy enough"...), yet merely having positive self talk ("I'm plenty good/worthy enough") can only partly ameliorate poor self esteem.
Self esteem seems to emerge naturally with a certain kind of self-intimacy and self-knowing, which goes deeper than mere thoughts and beliefs. One has to be well-grounded in one's embodiment and present-moment experience in order for self esteem to emerge, which it does naturally when such grounding is present.