This is something i learnt quite recently, unfortunately i see it happening between others and Id just like to share the following

A valuable life lesson :
Do not ever, tell someone what you know/heard about them. Even if they are related to you. If you can fix it, fix it otherwise shut it. Like, lets say, A comes to you and tell you something about B. Now B is someone you personally know, and you want to tell B about whatever it is that you have been told about them, to confirm or whatever. Dont do it. It’s seriously a major cause of fitnah. It will not only create problems between A and B, but will create problems between you and A. And it might just be that A turns around and stabs you in the back (serves you well!) and spread some gossip about you to B, and now you and B are on bad terms as well.

So, before you get yourself into all that mess, please keep quiet about anything that does not involve you. =)

Life will be so much easier. One less headache.