Love the truth, show yourself as you are, without pretenses and fears. . .and if the truth causes you persecution, accept it, and if it causes you some torment, bear it. And if for the sake of truth you should sacrifice yourself and your life, be strong in your sacrifice.
That timeless pearl of wisdom is really the only way to proceed, given that some interpret the truth as an attack on their very dignity, or what they hold dear. They may not be prepared to budge, even if they hear it said that moral truth is essential to finding real happiness and peace.