自信 (zì xìn): มีความมั่นใจในตัวเอง

She is very self-confident and never fears speaking in front of others.

After several months of practice, he became more and more confident in his spoken Chinese.

Lack of self-confidence can make people miss many opportunities.

She appeared very self-confident in the interview and left a good impression on the interviewer.

You should believe in yourself; don't always lack confidence.