Assure, Ensure, or Insure … When to Use Which
These three words cause a lot of confusion. There are some simple ways to remember which one should be used in what circumstance. I referred to the ultimate English reference tool, Fowler’s Modern English Usage, to ensure that I gave you the most accurate information on this sticky little problem.
Assure is a verb meaning to offer reassuring words in order to remove doubt. Example: Mark assured Helen that he had not forgotten their anniversary, and he pulled out a gift-wrapped box to prove it.
Ensure is a verb meaning to make certain. Example: Please ensure that these documents are mailed no later than March 1.
Insure is a verb meaning to protect an asset financially. Example: Irene insured her life for half a million dollars after her divorce left her with three children to provide for.
We can put them all in one sentence, thus: The agent assured us that if each of us insured our lives for $250,000 each, the policy would be sufficient to ensure that our children got a college education in the event of our premature deaths.
I hope that these examples and definitions provide you with the confidence to properly use these words in your writing and speech.