Some notes in clarification (?)
Merriam Webster Collegiate-
ensure....
"synensure, insure, assure, secure mean to make a thing or person sure. ensure, insure and assure are interchangable in many contexts where they indicate the making certain or inevitable of an outcome, but insure sometimes stresses the taking of necessary measures beforehand and assure distinctly implies the removal of doubt and suspense from a person's mind. secure implies action taken to guard against attack or loss."