The vain man is not sincere, and, in the bottom of his heart, is very seldom convinced of that superiority which he wishes you to ascribe to him.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“He affects even to despise it, and endeavours to maintain his assumed station, not so much by making you sensible of his superiority, as of your own meanness. He seems to wish, not so much to excite your esteem for himself, as to mortify that for yourself. The vain man is not sincere, and, in the bottom of his heart, is very seldom convinced of that superiority which he wishes you to ascribe to him. He wishes you to view him in much more splendid colours than those in which, when he places himself in your situation, and supposes you to know all that he knows, he can really view himself. When you appear to view him, therefore, in different colours, perhaps in his proper colours, he is much more mortified than offended.” source