Marion Meade,
Dorothy Parker: What Fresh Hell is This? (1988; rpt. New York: Penguin Books, 1989), p. 311 (on Alan Campbell's decision to enlist in the Army; brackets in original):
Among those praising Alan's decision as deeply courageous was Gerald Murphy, who presented him with a wristwatch engraved with the admiring but melodramatic inscription, QUI SENSAT ACET [He who feels, acts].
I don't know any language in which "qui sensat, acet" is a grammatical or meaningful sentence. Perhaps it's a mistake for Latin "qui sentit, agit". Ian Jackson (via email) agrees and suggests:
I suspect that someone saw the motto in Latin, had it explained to him in English, remembered feeling as "sensitivity" and acting as "agitate" and attempted a memorial reconstruction of the Latin using some such paradigm as "bis dat qui cito dat".