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Assure vs. Ensure vs. Insure

Insure, ensure and assure are often mixed up in writing, arguably because they have similar meanings and spellings. However, the differences between the three words are clear, and, in most cases they should not be used interchangeably. Insure is a verb that means to cover with an insurance policy, a contract between a person, a policy holder, seeking coverage and a company that protects them in case of an event. The insurance company provides compensation if there is damage to the insured person or their belongings, such as their car being damaged in an accident or a necklace being stolen. When we use the word insure, we are nearly always referring to this contractual situation.
  • I’d like to insure my car for one year.
  • My house was insured in case of flood damage, but I didn’t insure it for other natural disasters.
Ensure is a verb that means to make sure something will happen. It is often confused with insure. However, ensure has a much broader usage and meaning, whereas insure refers to a financial agreement.
  • I will study hard to ensure I get good grades.
  • Emily’s brilliant performance ensured a sixth successive win for her team.
Assure is a verb that means to address the doubts or insecurities of a person. If you assure someone, you will relieve them of their doubts, or give them confidence that something will or won’t occur. Assure is only used when talking about people, or in some cases, animals.
  • assure you that I will finish the job.
  • The dog, assured by its master’s gentle whistle, stopped barking.

How to Use Insure vs Assure vs Ensure

Let’s take a look at these examples, which use insure and assure incorrectly.
  • By studying extra hard, I hope to insure that I will do well in my exams.
Insure is incorrect here, as it implies that an insurance policy is taken out. We know that is not possible.
  • By studying extra hard, I hope to assure that I will do well in my exams.
Assure is incorrect here, as we know it means to remove the doubts of someone. The only way we could make the sentence grammatically correct is by adding a person after assure.
  • By studying extra hard, I hope to assure my mother that I will do well in my exams.
The correct word to use in the example is ensure:
  • By studying extra hard, I hope to ensure that I will do well in my exams.
Remember, insure is only used in reference to an insurance policy, ensure means to make sure and assure means to relieve someone of their doubts.

What Does Assure Mean?

Assure means to give someone confidence (that something will or won’t happen) or to remove someone’s doubts about something (usually by telling them something positive). Some examples of assure in a sentence:
  • We assure you, this project will be delivered on time.
  • The president was able to assure voters she would challenge the proposed decision.
  • The sun, I assure you, will still come up tomorrow.
Remember that assure is a verb, so is subject to conjugation and changes in tense:
  • Jen assures Mark that they will win the race.
  • assured my friends that I would soon recover.
  • After assuring him she would come home soon, she gave him a quick kiss and went to work.

Confusion of assure and ensure

Assure means to give someone confidence that something will happen, whereas ensure means to make sure that something happens. You can see why there can be some confusion between the two. Look at these two similarly themed sentences as an example
  • Assured of victory, the coach benched his star player.
  • Victory ensured, the coach benched his star player.
This is tricky, but in the first example, assured of victory is referring to the coach’s thoughts (remember, we assure a person, so in this case the coach assured himself). Whereas in the second example, victory ensured is a more general statement that victory will definitely happen, not relating to the coach’s thoughts, but to the almost universal feeling that victory was (nearly) guaranteed.

What Does Ensure Mean?

Ensure means to make sure or guarantee, normally in the sense of making sure a particular outcome occurs. Some examples of ensure in a sentence:
  • To ensure that there is no confusion, everyone must wear nametags.
  • ensure victory by cheating every time.
  • We will ensure that you don’t forget it.
Remember that ensure is a verb, so is subject to spelling changes according to conjugation and tense change:
  • Bob ensures the safety of himself and his passengers by driving carefully.
  • The Celtics ensured the win with 40 points in the last quarter.
  • Your parents want to ensure you understand their concerns.

Confusion of ensure and insure

It is easy to confuse insure and ensure. In fact, according to some style guides, it is technically correct to use insure to mean ensure. For example, the New York Times suggests the two words are interchangeable. However, the trend in American English seems to point towards distinguishing between insure and ensure, with the former meaning to provide or take an insurance policy and the latter having the broader meaning of making sure something occurs.

What Does Insure Mean?

Insure means to provide or obtain an insurance policy. Effectively, this means entering into a financial contract with a company to provide compensation if a particular (usually negative) event occurs. Some examples of insure in a sentence:
  • How much money did it cost to insure your car?
  • You should always insure your home for fire damage.
  • A good singer should insure their voice for millions.
Remember that insure is a verb, so subject to spelling changes with conjugation and tense:
  • How many years have you been insured to drive that car?
  • AIG insures millions of Americans.
  • After insuring her diamond ring for thousands, she lost it the next week!

Confusion of Insurance and Assurance

Two further words, relating to insure and assure, are often mixed up in speech and writing. Insurance, as we have seen, relates to financial products, but it has entered common parlance with a more symbolic meaning. For example, we might see sentences like the following:
  • There was an extra doctor in the room, a kind of insurance policy in case something went wrong during surgery.
  • The batter added some extra insurance with a home run towards the end of the game.
As you can tell, these wouldn’t be actual insurance policies. Instead, they use the word insurance as a metaphor to emphasize their desire to guarantee an outcome. Assurance is a noun meaning a declaration to give confidence. However, it is also a financial product, especially prevalent in the UK, that is associated with life insurance, so you can see why the two get mixed up. Normally, assurance is used to mean promise or promises:
  • She gave an assurance that she would arrive by 9pm.
  • Congress gave assurances that the bill would pass.
Please note: there is no such word as ensurance. In most cases, we would use assurance instead.