The character you seem to have is only your pride. Unless it's exerted it's of no value. Which means you have to get into situations where your pretence gets stripped for your character to show. Only then someone will attach significance to your character.
Probably you give too much attention to what meets your eye. One simple exercise is acting as if you are blind or closing your eyes while talking.
Practice asserting by writing. You may not be able to react at a given moment. But later you can write about how you really wanted to react. This will give you some self confidence.