Mendaci, neque cum vera dicit, creditur.
(M. Tullius Cicero, De Divinatio 2.71.146, adapted)

One does not trust a liar even when he speaks the truth.

(pron = mehn-DAH-kee NEH-kweh koom WAY-rah dee-kit KREH-dih-toor)

Comment: This is a pretty straight forward piece of wisdom which most people
come to see in one way or another. Sadly, we learn this dynamic only after
having been lied to by someone that we trusted. Thereafter, trust in this
person is difficult, even if we wish to begin trusting him/her again. Cicero's
comment points out another twist in the problem of trust between people. The
one who once betrayed is still capable of telling the truth. But, how does one
know and discern the difference?

I don't see any easy way of dealing with trust and betrayal. It does seem to
me, though, that if we practice our own integrity--that is--daily asking
ourselves in front of the mirror how true we are being in word and deed to who
we really are, that we develop a kind of radar. We sense our own lies. We
sense our own truth. Integrity means owning our own lies and truth, which
enables us to recognize both in others.

This is not science. This is the art of being human. It requires daily
practice.