Confidence isn’t a personality trait. It’s what preparation feels like from the inside.

What looks like natural assurance is usually somebody who has done the thing enough times to know roughly what will happen. The feeling arrives after the preparation rather than before it, which is why trying to summon it directly rarely works and often makes matters worse. Treating it as a trait leaves you waiting for something that was always a result.

Rather than working on how you feel about it, run through the thing once more than you think you need to. Prepare the first two minutes especially, since that is where the nerves live. The steadiness turns up on its own.