Use Assure, Ensure and Insure

The definitions of the three verbs assure, ensure, and insure overlap enough to make them synonyms in some cases. Most of the time, though, you can clearly divide them into three separate definitions.

Steps

Learning the Definitions

  1. Use assure when someone is being convinced. Assure means "to tell someone with confidence, removing doubt." If you are trying to convince or reassure someone, use assure. The object of the verb is usually a person. Here are a few examples:
    • "I assure you, I'm not dead."
    • "Can you assure me that you will be here?"
    • Having never been on a plane before, Delilah was anxious. A more experienced traveler assured her that flying was safe.
    • "Stand firm in your refusal to remain conscious during algebra. In real life, I assure you, there is no such thing as algebra." –Frances A. Lebowitz
  2. Use ensure when something is being guaranteed. Ensure means "to make certain that something will happen." The object of the verb is always a thing, never a person. If you are taking action to guarantee the result you want, use "ensure."
    • To ensure your cooperation, we have posted armed guards throughout the facility.
    • Ensure that it does not happen again.
    • I ensured our safety by locking the door.
    • Cooking meat to the proper temperature ensures that you don't become ill.
    • "To win the War, to overcome the enemy upon the fields cannot alone ensure the Victory in Peace. The cause of War must be removed." —Haile Selassie I
  3. Use insure when dealing with financial insurance. Insure means "to arrange for compensation in case of damage or loss." Although it sounds similar to the other words, it almost always refers to a financial agreement. There is no need to use it in any other context.
    • Tippecanoe Mutual will insure your vehicle for accidental damage or theft.
    • I make regular payments to a company so that my home is insured against damage. If lightning strikes my home, the company will pay me to compensate for the damage.

Corner Cases

  1. Learn the overlap between assure and ensure. Occasionally, assure can also mean "to make something certain to happen". This is most common in the phrases "assure success" or "assure victory." Since these definitions overlap, the author's judgment or personal preference determines which word is best.
    • For example, "We have ensured victory" and "We have assured victory" are both correct. Ensure is the more common usage.
  2. Understand assure used as insure. In British English, assure is sometimes used instead of insure. For example, an English bank might "assure" a sum of money in case of damage, or "assure" your life (grant you life insurance).[1]
  3. Accept insure used as ensure. In American English, insure is occasionally used instead of ensure.[2]
    • For example, some people might say "We hired a caterer to insure an excellent meal," but ensure is the more common usage. Some grammar guides consider ensure the only correct usage here, but others disagree.

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