Here is a new way of looking at sincerity. The Latin root of the word sincere is “sin-cere” meaning without wax. It comes from a time when selling marble to sculptors and stone masons was big business. Disreputable stone sellers would hide the flaws by filling cracks in their marble with wax so that a “sincere” dealer was one who did not cover over or hide flaws with wax.
What if the way that we are sincere is by not hiding or covering our flaws? To go as-is, as we are, allowing our flaws and yes our cracks, to show.