They gave you the respect to tell you the bad things, and they betrayed someone's trust by telling you the information. Do you really think they're really going to betray someone's trust by telling you who it is? Just be grateful that they've told you. You didn't have to know the information.
That person could be a friend, who they don't want to lose their friendship over.
That person could be an informer, who they don't want to lose their source of information over.
That person could be someone you regularly live with, who they don't want to cause conflict in your relationship over.
What's an assertion, and what should I type in?
Compesh is a question and answer (and debate) website, so before you make a debate, you better learn what an assertion is. I suppose you already know what a question is, and that you've typed it in the box. ;)
An assertion, is basically a statement you can make, that is either true or false.
Richer people have better health.
The question for that would be, Do richer people have better health?
And don't forget to make your assertion, match your question.
psychology
That person could be a friend, who they don't want to lose their friendship over.
That person could be an informer, who they don't want to lose their source of information over.
That person could be someone you regularly live with, who they don't want to cause conflict in your relationship over.