From WordNet (r) 3.0 (2006):
ensure
v 1: make certain of; "This nest egg will ensure a nice
retirement for us"; "Preparation will guarantee success!"
[syn: guarantee, ensure, insure, assure, secure]
2: be careful or certain to do something; make certain of
something; "He verified that the valves were closed"; "See
that the curtains are closed"; "control the quality of the
product" [syn: see, check, insure, see to it,
ensure, control, ascertain, assure]