Is it ensure, insure, or assure?
c.1200, "to strike with the fist or hand; cuff, box, slap; from Old French bufeter "to strike, slap, punch," from bufet (see buffet (n.2)). Related: Buffeted; buffeting.
"table," 1718, from French bufet "bench, stool, sideboard," 12c., of uncertain origin. Sense in English extended 1888 to "meal served from a buffet."
c.1200, "blow struck with a fist or weapon," from Old French bufet "slap, punch," diminutive of bufe "a blow, slap, punch; puff of wind," figuratively "cunning trick," probably echoic of the sound of something soft being hit.