Quite possibly, this is the cruelest thing that you could do to someone. Particularly when you don't understand it or only know part of the truth (at best), anyway. Let people live; let people learn. (Those are not my words but well said.
People change so you can learn to let go, things go wrong so that you can appreciate them when they're right, you believe lies so that you will eventually learn to trust no one but yourself, and sometimes good things fall apart so better things can fall