Wilde is not dismissing sincerity itself, but rather suggesting that artistic truth operates on a different frequency than moral earnestness—a distinction most people muddle. We mistake an artist's honest feelings for the work's power, when really a brilliant forgery, a calculated exaggeration, or even a beautiful lie can move us more than raw autobiography ever could. Watch how a skilled actor can portray grief more convincingly than someone genuinely bereaved, simply because the actor understands form, timing, and selection in ways the heartbroken person does not. The quote frees us from the tyranny of assuming that only "authentic" work deserves our attention.