How do I gain confidence like this guy?

How do I gain confidence like this guy? This guy has so much confidence I literally don’t understand. Watch these 2 videos https://youtu.be/5tN8zQgDtSQ This video literally made me tear up because of his confidence and the way people reacted to it. It’s amazing. But look at how good his confidence is now https://youtu.be/JdMMunwO0R0 When I stutter around people I try to hide it by taking pauses/saying “uhhh” or avoiding words. But this guy doesn’t get nervous just lets the stutter be. How the heck do i gain a confidence like his? When I stutter I start sweating a lot as well. I just want this confidence