Is it ensure, insure, or assure?
Old English cresse, originally cærse, from Proto-Germanic *krasjon- (cf. Middle Low German kerse, karse; Middle Dutch kersse; Old High German kresso, German Kresse), from PIE root *gras- "to devour" (see gastric). It underwent a metathesis similar to that of grass. French cresson, Italian crescione are Germanic loan-words.