Recently I was editing a book (on a financial topic) and a few times I corrected the author’s use of two commonly confused
words: “insure” and “ensure.” Because many others have trouble distinguishing the shades of meaning with these words, I
thought I’d do my part to clear up the confusion, and have thrown in a third similar word to the mix: assure. First, the
definition, then an example.
Assure: to declare earnestly, with sincere intention. “He assured her he would be forever faithful.”
Ensure: to make certain or guarantee something: “She bought her son twenty pairs of socks to ensure he was never without clean
ones between washings.”
Insure: to guarantee against loss or harm.”He insured his life for a half million dollars so his family wouldn’t struggle if
he met an early death.”
Here’s a quick cheatsheet to check your usage:
Assure: Think of the word “reassure.” Very similar meaning.
Ensure: Think of “make certain.”
Insure: Similar to ensure, but there’s usually a financial guarantee.