Is it ensure, insure, or assure?
early 14c., "a coming for the purpose of attack," from Old French venue "coming," from fem. past participle of venir "to come," from Latin venire "to come," from PIE root *gwa- "to go, come" (cf. Old English cuman "to come;" see come). The sense of "place where a case in law is tried" is first recorded 1530s. Extended to locality in general, especially "site of a concert or sporting event" (1857). Change of venue is from Blackstone (1768).