我真心无法在没有你的情况下完成这件事。

___Truly, I could not have done this without you.

他真心相信自己单凭意志力就能治愈自己。

He ___truly believes he can cure himself by willpower alone.

我真心相信，只要有耐心，我们终会成功。

I ___truly believe that, with patience, we will succeed in the end.