Is it ensure, insure, or assure?
1590s, "place for assembling of troops," from Middle French rendez-vous, noun use of rendez vous "present yourselves," from rendez, plural imperative of rendre "to present" (see render (v.)) + vous "you," from Latin vos, from PIE *wos- "you" (plural). General sense of "appointed place of meeting" is attested from 1590s.
1640s, from rendezvous (n.).
1. In Ada, the method of synchronising the activity of different tasks.
2. Query language, close to natural English.
["Seven Steps to Rendezvous with the Casual User", E. Codd in Data Base Management, J.W. Klimbie et al eds, N-H 1974, pp.179-199].