self-confident
adjective approving uk/ˌselfˈkɒn.fɪ.dənt/ us/ˌselfˈkɑːn.fə.dənt/
B2 自信的，信心十足的
behaving calmly because you have no doubts about your ability or knowledge
At school he was popular and self-confident, and we weren't surprised at his later success. 在学校的时候，他很受欢迎又很自信，所以对他以后的成功我们丝毫不感到惊讶。
Synonym: self-assured
See also: confident