Many are those who now constantly claim to be “truthful” or “authentic” to assert their legitimacy, feeding into a glorification of transparency. Whether in the management of private organizations or from a political point of view, or even in our most basic interactions with others, sincerity has become a “pretext” that would guarantee the validity of certain actions or decisions. Such is the objective of those who, speaking or acting under the guise of “sincerity”, claim to be legitimate, untouchable, and credible. However, what is sincerity? Is being sincere even possible? In the age of social networks, where we are constantly wavering between truth and illusion, what meaning can we assign to “sincerity,” this inescapable virtue, at times thought capable of “healing” our contemporary world? In this essay, the author gives us the keys to better withstand the difficult transition towards contemporaneity. She provides us here with a true blueprint of an ethical life.