I agree with you, there totally is a difference in projecting confidence and feeling it. I’m terms of stuttering, I think MOST people who stutter, obviously lack confidence in ANY situation where they are required to verbally communicate. However, there are lot of other things that can make someone confident. Like for example, let’s say someone is physically attractive…they may have a general sense of confidence daily, however if that person also stutters badly, then in speaking situations they may feel less confident in themselves. Like I personally am really good at making and playing music. I am very confident in my ability to play an instrument, however, as soon as I have to speak…boom there goes that confidence. And yes there totally is a huge level of uncertainty when speaking, most people who stutter have situations where their stutter isn’t as bad, but then others it’s really bad. I personally, feel uncertain everytime I open my mouth. Idk if I’ll say what I wanna say fluently or if I’m gonna block and have a lot of repetitions.