Barbara of the Bonneville Power Administration in Vancouver, Washington, asked me to write about ensure, assure, and insure. I am happy to write from the U.S. perspective, and I am hoping my friends across the oceans and borders will enlighten us about any differences.
Here is an illustration with all three words:
I assure you that Morgan did ensure that the company will insure both vehicles.
Here are quick definitions based on my favorite U.S. style guides:
Ensure = make certain.
Insure = protect against financial loss.
Assure = promise, give confidence to.
The noun form of insure is insurance. Outside the insurance industry, some people use insure and ensure interchangeably, but careful writers don't.
Let's see if we agree which word goes in each blank:
- Please _____ that this does not happen again.
- You ought to _____ the painting for $24,000.
- Please _____ Mrs. Rio that her coat will be delivered to her today.
- How can I _____ that the package will arrive by tomorrow?
- I _____ you that the figures are correct.
Before I give you my answers, remember my sample sentence with all three words? Please forget it. It would never be wise to use all three words in one sentence. Doing so would dizzy your readers rather than focusing them on your meaning.
Here are my answers for the blanks above: 1. ensure, 2. insure, 3. assure, 4. ensure, 5. assure.
Please let me know what works in Britain, Australia, Canada, and other lovely places.
Lynn
Syntax Training
P.S. If you like simple explanations of confusing word pairs, get my "60 Quick Word Fixes." It's available as a PDF and booklet here.


Yes, all of this is true for us in the UK.
Posted by: Clare Lynch | August 25, 2008 at 04:29 AM
Thanks for confirming, Clare. Let's see if others have the same experience.
Posted by: Lynn | August 26, 2008 at 07:53 AM
It would be the same in Canada if linguistic skill was a universal gift.
I know many people who would argue that both ensure and insure could be used in examples one and four. I do my best to err on the side of kindness.
Posted by: Morley Tuttle | October 16, 2008 at 01:42 AM
Kindness--that's a rule that supersedes the others. Thanks for commenting, Morley.
Posted by: Lynn | October 24, 2008 at 12:08 PM
Pls give a sample letter for thanks giving to my Life Insurance Business clients
Posted by: Sudheer Kumar V | January 09, 2012 at 06:10 PM
Sudheer, I have written many blog posts about thank-you messages. Please type "thank-you" in the search box at top right, and you will find a list of things I have written, including examples.
Lynn
Posted by: Lynn Gaertner-Johnston | January 10, 2012 at 04:52 PM