A wit should be no more sincere than a woman constant.
A little sincerity is a dangerous thing, and a great deal of it is absolutely fatal.
Every man alone is sincere. At the entrance of a second person, hypocrisy begins.
The value of an idea has nothing whatever to do with the sincerity of the man who expresses it.
Nothing astonishes men so much as common sense and plain dealing.
Insincerity is merely a method by which we can multiply our personalities.
Of all the evil spirits abroad at this hour in the world, insincerity is the most dangerous.
Sincerity is not a test of truth – It is possible to be sincerely wrong.
The true hypocrite is the one who ceases to perceive his deception, the one who lies with sincerity.
The secret of success is sincerity. Once you can fake that you’ve got it made.