Is it wise to ever trust what another person says about someone else that you know?
Depends on the feed back, source of the information, and the "respect" recognized or valued between the individuals.
The best advice I have ever been given is "Dont believe anything you hear, and only half of what you see."
To what degree is gossip okay?
no i get this a lot and if i dont see it for myself i never believe anything they say about my friends and if i have any doubts i just ask them up front....