self-assured 与 confident 有什么区别？

没什么大区别。self-assured 比confident更具体一些。
例句：You're quite shy and you aren't very confident.
你很害羞，不够自信。
A person of impressive skill and daring, especially one who is highly successful and self-assured.
艺高胆大之人，尤指极为成功或自信的人

self-assued 用在句尾

be confident in 用在句中