“Being honest may not get you many friends, but it will always get you the right ones.” The best I can tell, this quote is attributed to John Lennon. 

The art of being honest with friends can be tricky. Some are blessed with the art of diplomacy and can say pretty much anything, and you'll thank them for it. Most don't say anything, while others carry and dispense truth like a hammer.

IMHO If you want your relationships to be deep and meaningful, you must be honest. Just do it with love.