Is it ensure, insure, or assure?
mid-15c., perhaps from Middle French tiretaine "strong, coarse fabric" (mid-13c.), from Old French tiret "kind of cloth," from tire "silk cloth," from Medieval Latin tyrius "cloth from Tyre." If this is the source, spelling likely influenced in Middle English by tartaryn "rich silk cloth" (mid-14c.), from Old French tartarin "Tartar cloth," from Tartare "Tartar," the Central Asian people (see Tartar).
an Assyrian word, meaning "the commander-in-chief." (1.) One of Sennacherib's messengers to Hezekiah (2 Kings 18:17). (2.) One of Sargon's generals (Isa. 20:1).