Speaking with confidence conveys your knowledge or mastery (i.e. competency) of the information you’re sharing, and it makes a difference in the way people see you at work.
It might not be fair but it’s true.
So speak with confidence and practice out loud what you think you’re going to say in critical conversations.
As someone who talks for a living, I do it. All. The. Time.
I rehearse questions before post-game interviews.
I practice scripts before going on-air.
I verbalize the introduction I’m going to make when I meet a new player or coach in the locker room.