Is it ensure, insure, or assure?
1590, first recorded in Shakespeare, who used it often; perhaps a variant of harry (v.), or perhaps a West Midlands sense of Middle English hurren "to vibrate rapidly, buzz," from Proto-Germanic *hurza "to move with haste" (cf. Middle High German hurren "to whir, move fast," Old Swedish hurra "to whirl round"), which also perhaps is the root of hurl. Related: hurried; hurrying.
c.1600, probably from hurry (v.).