"For Lacan, ‘full speech’ took place on the level of the Symbolic; here was where meaning was produced and expressed. By contrast, ‘empty speech’ occurred at the level of the Imaginary, a pure signification devoid of true meaning... ‘Full speech is speech which aims at, which forms, the truth such as it becomes established in the recognition of one person by another. Full speech is speech which performs"

This is a different cut on the question of earnestness and sincerity, and I find it quite powerful.