Politeness does not always imply goodness, equity, obligingness and gratitude; it at least provides the appearance of these, and makes a man seem outwardly what he should be inwardly.

[La politesse n’inspire pas toujours la bonté, l’équité, la complaisance, la gratitude; elle en donne du moins les apparences, et fait paraître l’homme au dehors comme il devrait être intérieurement.]

Jean de La Bruyère (1645-1696) French essayist, moralist

The Characters [Les Caractères], ch. 5 “Of Society and Conversation [De la Société et de la Conversation],” § 32 (5.32) (1688) [tr. Stewart (1970)]
    (Source)

(Source (French)). Alternate translations:

Politeness does not always inspire Generosity, Equity, Complaisance, and Gratitude: it gives a man the appearances of those Vertues, and makes him seem that without, which he ought to be within.
[Bullord ed. (1696)]

Politeness does not always inspire Generosity, Justice, Complaisance and Gratitude; it gives a Man the Appearances of those Virtues, and makes him seem that without, which he ought to be within.
[Curll ed. (1713)]

Politeness does not always produce kindness of heart, justice, complacency, or gratitude, but it gives to a man at least the appearance of it, and makes him seem externally what he really should be.
[tr. Van Laun (1885)]