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》

She treats me aS her closest friend.

她把我看作是她的最亲密的朋友。

youdao

He was stretched out in the casket; the wife was sitting there in black next to her closest friend.

躺在棺材里，他的妻子穿着一身黑衣坐在她最好的朋友边。

youdao

Jagger, 57, was accompanied by one of Hall's closest friends Tharita de Serra - a friend from her early modelling days - who flew into Britain for the occasion.

BBC: Mixed reviews for Hall's nude debut