Booher's Rules of Business Grammar - Dianna Booher 2009

Do i have your guarantee?
Misspelled and misused words

ENSURE, INSURE, ASSURE?

The synonyms ensure, assure, and insure mean to give a guarantee. Synonyms can replace each other in some contexts—but not in all. For example, big, large, huge, gigantic, and enormous are synonyms. But these words can’t always be used interchangeably. I might say, “Hortense gave a big speech to all the employees last week about cutting expenses.” But I wouldn’t say, “Hortense gave an enormous speech to all employees last week about cutting expenses.”

Synonyms are similar, but they’re not interchangeable in all contexts. So back to ensure, assure, and insure.

Ensure (to guarantee or make certain—use in cases other than when referring to people):

This new packaging will ensure that the product arrives safely.

Insure (to make certain or protect against loss—use when referring to monetary payments):

This bond will insure payment up to $2,000.

Assure (to pledge or give confidence to people—use in the same way as reassure):

He assured us that he would attend.

Her e-mail assured the customer that our report would be submitted before the deadline.

Memory tip

Insure: Insurance companies spell their names with an —i. They make monetary payments. Use the —i word when talking about money.

Assure: People reassure you. Use the —a word when talking about people giving assurances.

Ensure: Use the —e word in all other situations.