Is it ensure, insure, or assure?
1540s, possibly an alteration (by association with rake (n.1) and Hell) of Middle English rakel (adj.) "hasty, rash, headstrong," probably from raken "to go, proceed," from Old English racian "to go forward, move, hasten," of unknown origin. Cf. rakeshame (n.) "one who lives shamefully" (1590s).