You don't judge people so much on what they say. You judge them on what they do. That applies to both men and women. ("By their fruits you shall know them.")
I read a lot of articles in the Manosphere on being confident. A lot of the advice is bullshit. "Fake it until you make it." "Women like insanely confident men." (I've seen guys like that thrown out of bars by bouncers.)
Nope, it's all crap.
You become confident by being good at what you do. And what you are good at, you like. But it takes weeks, or months, or even years to become very good at what you like.
I am reminded of the last scene in Breaking Bad (although Walter White destroyed his life through Hubris):
"I liked it, I was good at it, I felt alive."
However, Hubris followed by Nemesis is what happens from being "insanely confident" and not knowing your limitations (the Greeks called that Sophrosyne (the "goddess or spirit (daimona) of moderation, self-control, temperance, restraint, and discretion").
“Believe in yourself! Have faith in your abilities! Without a humble but reasonable confidence in your own powers you cannot be successful or happy.” ― Norman Vincent Peale
The Four Cardinal Virtues (essential advice for everyone) refers to confidence as Courage (which is perseverance). It's tempered by Prudence, which is choosing the right path among many (White choose the wrong path). Included are Self-Control and Justice (giving each his due).
You become confident by being good at what you do, and liking them. And what you are best at, you almost always are born with that talent, although you have to practice at it.
However, you become good at a lot of things by practicing. Some examples: I've pulled the heads off of engines and redone them, built a rocking chair out of black oak, cooked steak with mushrooms and potatoes with broccoli, built computers from scratch, designed and built houses. I can do those things not because I'm insanely confident, but because I learned how to do them.
I can make sourdough bread, and I remember in college one girl came into my apartment, looked at the sourdough starter, then looked at me with her mouth open. "You can do that?" she asked in awe. "I can do a lot of things, and I can do all of them well" I told her, and gave her a big smile.
When it comes to women, I've always had a natural talent at being funny (the Manosphere uses that ignorant word and inaccurate word, "negging"). I could have been a stand-up comedian, and in many ways I am.
And I don't listen to anyone who puts me down, which happens a lot when I point out to people they don't know what they're talking about and instead I'm supposed to agree with their uninformed opinions. (Usually putting someone down is done out of envy.)
“You have no responsibility to live up to what other people think you ought to accomplish. I have no responsibility to be like they expect me to be. It's their mistake, not my failing.” - Richard P. Feynman, Surely You're Joking, Mr. Feynman!
I was recently standing behind a woman who did not know I was there, and I heard her say about me: "That guy is funny." When she turned around and saw me, I said nothing but gave her a mischievous look. She had no idea what to say to me.
In college one guy I knew (who today would be called a PUA) once told me, "You don't seem to go after women a lot." "They go after me," I told him, and he, too, was speechless.
There are a lot of things I cannot do. I can't sing, I can't dance, and I can't play any instruments. But there are a lot of things I can do. I'm good at them because I practiced, and because I like doing them.
One thing that is imperative is to not listen to people who tell you that you that you cannot do it. I get the impression that is what happens in school today, when young boys are told, "You can't do it," and are humiliated and put down. They're not allowed to be boys anymore.
“I do not care so much what I am to others as I care what I am to myself.” ― Michel de Montaigne
You have to not care what others think. That self-consciousness will destroy your confidence. It's exemplified by that sticker I used to see on cars: "No fear."
True confidence is based on being competent at things, not on bluster and a big mouth and nothing to back it up.
“You gain strength, courage and confidence by every experience in which you really stop to look fear in the face. You are able to say to yourself, 'I have lived through this horror. I can take the next thing that comes along.' You must do the thing you think you cannot do.” - Eleanor Roosevelt, You Learn by Living: Eleven Keys for a More Fulfilling Life