CORPORAL: [trying to copy Lawrence’s snuffing a match with his fingers] Ow! It damn well ‘urts!

LAWRENCE: Certainly it hurts.

CORPORAL: Well what’s the trick then?

LAWRENCE: The trick, William Potter, is not minding if it hurts.

Robert Bolt (1924-1995) English dramatist

Lawrence of Arabia, Part 1, sc. 18 (1962) [with Michael Wilson]
    (Source)

(Source (Video)). In the actual film, the last line is given, "not minding that it hurts."