一个最可靠的朋友，固然往往会是你最可怕的仇敌，但一个可怕的对手，往往也会是你最知心的朋友。 。

One eof the most reliable friend, is often is your worst enemy, but a terrible opponent, often also is your best friend.

youdao

我的一生中没有一个知心朋友，就连我最信任的朋友也背叛了我。

In my life a intimate friend, I most has not trusted the friend has also betrayed me.

youdao