ensure

/in-ˈshu̇r/

Middle English, from Anglo-French ensurer, alteration of assurer

verb

  1. to make sure, certain, or safe : guarantee

ensure insure assure secure mean to make a thing or person sure. ensure insure, and assure are interchangeable in many contexts where they indicate the making certain or inevitable of an outcome, but ensure may imply a virtual guarantee , while insure sometimes stresses the taking of necessary measures beforehand