自信的英语单词是confident，名词形式是confidence。

confident

adj.确信的，深信的; 有信心的，沉着的; 自信的;

n.知己; 心腹朋友;

比较级：more confident 最高级：most confident复数：confidents

[例句]

I am confident that everything will come out right in time我坚信一切终究都会好起来。

In time he became more confident and relaxed 。过了一段时间，他变得更加自信、更为放松。

I am confident in him. 我对他有信心。

I think people feel a bit more confident 我想人们应该觉得稍微自信了一点儿。

I admired him for being so confident at his age. 我钦佩他这般年纪就如此自信。