If someone criticizes me or even insults me, I willingly invite them to do so provided their intention is good. If we can see that someone has a fault and just say that there is nothing wrong, then that is pointless and does not help at all.  If we tell the person that what they are doing is not too serious and later speak badly of them behind their back, that is not good either.  We should say what we think to their faces.We should clarify what is necessary, and separate truth from falsehood. If we doubt then we should express them.  Even if our words are a little harsh, we should say them anyway.  It will clarify our thinking and any gossip will be unfounded. But if we confine ourselves to smooth-tongued and polite remarks, there will always be a basis for distorting rumour. Personally, I prefer direct talking.