What does self-confidence mean?

What does self-confidence mean?

I have a very low self-confidence, I'm 21 years old

According to my friends, I am a handsome and stylish person who knows how to dress.

but I've never been in a relationship. Of course, I take responsibility for this on myself. after all i'm embarrassed to go and talk to girls (i can't talk to people in general)

But more importantly, I've been studying diction for months and working on articulation for hours, but I still can't speak properly when talking to people because I don't have confidence in myself.

Frankly, this makes me very sad. I feel like I'm not getting paid for my hard work.

I feel sad when people who have nothing to do with diction and have not studied speak better than me.

What I really want to ask is how do we do any action (talking to girls, talking to people, talking nice, etc.) with confidence?

What does self-confidence mean?
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