Updated 19 September, 2022: Barbara of the Bonneville Power Administration in Vancouver, Washington, asked me to write about ensure vs assure vs 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.
To promote a stronger pace of economic recovery and to help ensure that inflation, over time, is at levels consistent with its mandate, the Committee decided today to expand its holdings of securities. – The New York Times
Obamacare seeks to insure millions more Americans and rein in sky-high medical costs. – The Economist
Many of the IG’s recommendations to assure such actions do not occur in the future have already been acted upon,” he said in the statement. – The Guardian
Ensure vs Insure vs Assure Quiz
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.
For more articles on confusing words, take a look at our similar words section.