Sincerity somehow equates to consistency. To feel sincerity, there must be persistence and constant effort that the counterpart would be able to feel, not just hear. It’s not about the amount of times you utter the words, but the actions you carry out in trying to prove a point. Argument points are just empty when you don’t see any movement. Being consistent will make people believe and feel the truthfulness of the words through the actions. If the act is bound to crumble, how about dropping it and begin with your heart?