Have you ever watched someone who seems incredibly confident on the outside, but when you get them out of their element, they're quite insecure and worrisome?
Of course you have. We all have. (At times, we are that person.)
This is because they have worked on what they believe confidence "should" look like, but have never developed real confidence, which is internal.
Real confidence is something that's inside of you. On the inside, confidence always looks and feels the same; that's why it's sustainable.
True confidence is all about being comfortable with yourself at all times. When you make a mistake, you learn from it and move on. When you succeed, you relish in the accomplishment for a moment, and then move on. When you feel good about something, you allow yourself to be aware of it and enjoy it, and then you move on. When you feel sad or down, you acknowledge it, allow yourself to feel it, decide what you're going to do about it...and move on.
Internal confidence is about acknowledging, understanding, taking action and moving forward.
This process is about being in control of you, no matter what else is going on.
When you are in control of you, you can make deliberate choices as to how your confidence is going to look on the outside. It's not left up to chance or contrived. It's simply how you show-up.
On the outside, you may choose what confidence looks like based on the environment, the personalities in the room, or the situation. Culture may be a factor in your outward choices, as well, since not all behaviors exude confidence in different cultures (if you don't take the time to explore that when working within cultures other than your own, it can backfire and cause you embarrassment at best and offending others at worst).
Sometimes, you see people trying to "act" confidently (outward only), but what those people are often trying to do is take control of the situation, other people, or the environment despite their own insecurity and lack of confidence.
Those with real confidence (internal) know that they will never be able to completely control the environment, other people, or all the situations they encounter. That's why they don't feel the need to do so. That one understanding alone takes a lot of pressure off, and allows you to show-up in a more calm and in control way.
When all of the 'outwardly' confident people quiet down and run out of things to say, the voices that you will hear belong to those with internal confidence. Think about people you encounter regularly. You may notice that many of the most vocal people are not the strongest; quite the contrary, they are often the most insecure.
That's why they often talk a lot more than they listen; they feel the need to be heard, not realizing that their behavior might be what's getting in the way.
Developing your internal confidence, and showing up with it everywhere because it has become who you are, allows people the chance to not only hear you, but to also want to listen.