What's the 'harm' in letting her leave early? = I don't see any 'harm' in letting her leave early. = There's no 'harm' in letting her leave early. [=letting her leave early will not hurt anyone or cause a bad result]
I want to be sure that no 'harm' will come to her. = I want to be sure that she won't come to any 'harm'. [=that she won't be hurt in any way]
He claims that he didn't mean any 'harm'. [=that he didn't mean to hurt or bother anyone]
(..) I told Gandalf I would keep you safe. And safe is where I'll keep you. The trees have grown wild and dangerous. Anger festers in their hearts. They will harm you if they can. There are too few of us now. Too few of us Nets left to manage them. The Black Gate of Mordor. Oh, save us. (..)2002 The Lord of the Rings: The Two Towers