Both mean to guarantee or to promise that something is true or that something will happen. "Assure" means to say or write the guarantee. Example: He assured me that the product would be delivered tomorrow. "Ensure" means to do something to make sure or guarantee that something happens. Example: A firewall helps to ensure that hackers don't attack your PC. "Is assured" (using that tense) is as Alan wrote above.

They mean the same. However, in common use assure refers more to the thing which happens, and ensure refers more to the action of making something happen. For example, our victory is assured because we ensured our victory. Victory is the thing which happens. Ensure is something we did which caused us to have the victory.

======= By Longman ======= ensure = make sure assure all other assure = guarantee, ensure, insure, secure Word origin for ASSURE Date: 1300-1400 Language: Old French Origin: assurer, from Medieval Latin assecurare, from Latin ad- 'to' + securus 'safe' ======= By WordNet ======= word ensure more widely also equals to synonyms = guarantee, ensure, insure, assure, secure