Is it ensure, insure, or assure?
c.1300, "deficiency, shortage," from Old Norse vant, neuter of vanr "wanting, deficient;" related to Old English wanian "to diminish" (see wane). Phrase for want of is recorded from c.1400. Meaning "state of destitution" is recorded from mid-14c. Newspaper want ad is recorded from 1897. Middle English had wantsum (c.1200) "in want, deprived of," literally "want-some."
Someone who aspires to be someone else, esp a star or hero: Rambo Wanna-be's/ A ''poser'' or a ''wanta be'' is someone who tries to be like someone else
[1980s+ California surfers & black street gangs; fr imprecise or dialectal pronunciation of ''want to be'']