He's a self-assured, confident negotiator.

他是个胸有成竹、很有信心的谈判者。

She was calm and self-assured.

她沉着有自信。

She is a remarkably calm and self-possessed young woman.

她是个特别沉着有自信的年轻女人。

She is clearly the most articulate and self-possessed member of her family.

显然，她是全家口才最好、最沉着冷静的人。

If you want people to listen to your opinions, you'll need to learn to be more assertive.

如果你想要别人听你的观点，你需要学会更坚定自信些。

Their daughter is an assertive little girl.

他们的女儿是个坚定自信的小姑娘。

She seems very sure of herself.

她好像十分自信。

He sounded so sure of himself that I didn't bother to argue.

他听起来很自信，我都不想和他争论了。

I was too nervous to do it, but my sister went right up to him (as) bold as brass and asked for his autograph.

我太紧张了，不敢去，但是我姐姐特别自信，大胆地走到他面前要他的签名。

The baby took its first uncertain steps.

宝宝迈出了最初的蹒跚的脚步。

He's very insecure about his appearance.

他对自己的长相没有信心。

She felt nervous and insecure.

她感到局促不安。

Last night's defeat has taken some of the wind out of the team's sails.

昨晚的失败，打消了这个团队的一些积极性。

He said I wasn't as good as I thought I was. That sort of took the wind out of my sail.

他说我没有自己想象的那么厉害。这打消了我的热情。

Winning the game will really boost the team's confidence.

赢得比赛肯定会增强团队的信心。

To boost my confidence I went for a haircut and bought some new clothes.

为了增强自己的自信，我去剪了个头发，买了些新衣服。