You are her closest friend and confidante.

你是她最亲密的朋友和红颜知己。

《柯林斯英汉双解大词典》

My closest friend, Kim, has lost interest in school and studying.

我最亲密的朋友金已经对学校和学习失去了兴趣。

youdao

Half of those surveyed in 16 countries say they go first to their closest friend to share their wishes and fears.

在16个国家中，接受调查的人有一半表示，他们首先会找到最亲密的朋友，与他们讲述自己的愿望和害怕的事情。

youdao

This really disturbs me,he says. The 1996 alliance between Israel and Turkey, made Ankara Israel's closest friend in the Muslim world.

VOA: standard.2009.10.27

You're losing your closest friend.

你失去了最亲近的朋友。

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Let's say, you're at a restaurant with your closest friend.

假如你和你的密友在餐厅吃饭。

I hate 课堂 - SpeakingMax英语口语达人

His closest friend is a skateboard, which I guess is a step up from Mark Zuckerberg.

NEWYORKER: Tangled Webs

It will do far more than undermine our closest friend and the most entrenched democracy in Latin America.

CENTERFORSECURITYPOLICY: Free trade: An antidote to Chavez

She is the Obamas' closest friend and has served as a political adviser.

CNN: Women gaining political power