Is it ensure, insure, or assure?
c.1300, "greatness, glory," from Old French majeste "grandeur, nobility" (12c.), from Latin maiestatem (nominative maiestas) "greatness, dignity, elevation, honor, excellence," from stem of maior (neuter maius), comparative of magnus "great" (see magnate). Earliest English us is with reference to God; as a title, in reference to kings and queens (late 14c.), it is from Romance languages and descends from the Roman Empire.