汉译英“我没有一个真正关心我的知心朋友”

I do not have even one true friend who really understands me and cares about me.

我没有一个真正关心我的知心朋友。

（even one, 强调一个都没有），true friend (真正的朋友）
understand me (了解我，知心）。

I don't have a trully friend who really cares about me.

我没有一个真正关心我的知心朋友

I do not have a alter ego who cares for me really

可以了。
跟我一样，一个知心朋友也没有唉