Is it ensure, insure, or assure?
"to pay out or away" (money or wealth), Old English -spendan (in forspendan "use up"), from Latin expendere "to weigh out money, pay down" (see expend). A general Germanic borrowing (cf. Old High German spendon, German and Middle Dutch spenden, Old Norse spenna). In reference to labor, thoughts, time, etc., attested from c.1300.