How can i do to be a confident person?

Assertiveness: Training is helpful. Please see a clinical psychologist. A book call "When I say No I feel guilty" may be helpful, or any book on Assertiveness. Peace and good health. Be gentle but strong, your best self.

Thanks for asking: Confidence comes from an understanding that all of us are human. We all have good qualities and things that we want to improve. Do the best you can do daily and avoid people that put you down or are unpleasant to you. Find things that you are good at and take pride in doing them well. Honor yourself by being kind to yourself and not putting yourself down when you make a mistake. Love yourself.