Is it ensure, insure, or assure?
1640s, "show of endearment, display of regard," from French caresse (16c.), back-formation from caresser or else from Italian carezza "endearment," from caro "dear," from Latin carus "dear, costly, beloved" (see whore (n.)). Meaning "affectionate stroke" attested in English from 1650s.
1650s, from French caresser, from Italian carezzare "to cherish," from carezza "endearment" (see caress (n.)). Related: Caressed; caressing.