Is it ensure, insure, or assure?
c.1300, "direct one's attention to," from Old French entendre, intendre "to direct one's attention" (in Modern French principally "to hear"), from Latin intendere "turn one's attention, strain," literally "stretch out, extend," from in- "toward" (see in- (2)) + tendere "to stretch" (see tenet). Sense of "have as a plan" (late 14c.) was present in Latin. A Germanic word for this was ettle, from Old Norse ætla "to think, conjecture, propose," from Proto-Germanic *ahta "consideration, attention" (cf. Old English eaht, German acht). Intended (n.) "one's intended husband or wife" is from 1767.