The adjective sure means confident and certain; when a person is assured, she is confident (as in “self-assured”). Assured can also be a noun, with a similar meaning as insured. (See Black’s Law Dictionary: “Thus where a wife insures her husband’s life for her own benefit and he has no interest in the policy, she is the ‘assured’ and he the ‘insured.’ ”) As the past tense of assure, the verb assured can mean “to give confidence to,” or reassure (restore confidence or assure again).
Confusion arises because, in the U.S., insure, ensure, and assure can all mean “to make certain.”
The board favors expansion, but success is not assured.
Wise planning will ensure a successful event.
The regulations were designed to insure your safety.
Think of ensure as “making sure” something will or will not happen; when you insure something of value, you seek payment for losses or damages that are covered by the terms of your insurance policy. Statements are often made to provide assurance, but they may or may not be backed up by actions!
(verb): Are you insured against potential losses?
Our house is insured by the company that runs those clever ads.
Remember that insurance (noun) is designed for protection:
My insurance policy will be expiring soon.
This contract provides insurance against a rate increase.
When you are taking affirmative steps to guarantee an outcome, ensure is often the best choice.
(verb): Please ensure that the belt is fastened securely before continuing.
Our quality control measures ensure that your data is safe.
Use assure when information, a pledge, or a guarantee is provided for the purpose of inspiring confidence.
(verb): I assure you, we will find the culprit.
We have been assured that construction will be completed as planned.
(verb): I was reassured after I heard the prognosis.
The gesture reassured me that his intentions are honorable.
(adjective): A few reassuring words would set our minds at ease.
(noun): I don’t blame her for wanting reassurance, but I can’t give it to her.
Are you sure you know when to use insure, ensure, and assure?