Insure vs. Ensure vs. Assure: What’s the Difference?

Grammar Rules updated on  July 12, 2023 3 min read

To assure is to make someone feel convinced or satisfied. To ensure is to make sure something happens. To insure means to cover something with an insurance policy.

Can you use these three similar-sounding words interchangeably? It depends on who you ask. According to the major English dictionaries, they all have the same broader meaning.

But it’s important to remember that dictionaries are not in the business of telling us what words should mean; they tell us how words are used. Some people see these words as synonyms, while others view them as distinct.

You might find that in a business setting no one gives your word choice a second look, while in an academic setting they mark your paper down for a wrong-word error.

Let’s look at some definitions and examples so that you use the correct word in every setting.

Meanings of assure, ensure, and insure

While any of the three word choices may work, if you want to make your meaning as clear as possible, it’s wise to stick to the commonly accepted definitions below:

Assure: to make yourself or someone else feel confident about something

Ensure: to guarantee that something will happen, such as through action or authority

Insure: to guard against risk by covering something or someone through an insurance company—a contract backed by payment or some other transaction

How to use insure vs. ensure

When does it make sense to use insure or ensure? Use insure when you’re talking about transactional protection, but ensure when a sentence is about guaranteeing a result.

My father insured his business’s building and delivery vehicles to ensure that he would be able to replace them or secure financial compensation if any natural disasters occurred.

Companies often recommend their employees get the annual flu shot to insure against unnecessary time off.

Seasoning your cast-iron cookware after every use ensures that food won’t stick when you’re cooking.

How to use assure vs. ensure

Ensure is typically about things or events, while assure is usually focused on people. Here are some examples involving these two words.

Amahle assured her son that he would do great on his test, but to ensure success, she made him go to bed early and eat a substantial breakfast.

Preparing to speak before Congress for the first time, Freya was self-assured about her message but less confident about her oratorical skills.

LeBron James’s long career and elite talent have earned him dozens of awards and ensured he ranks among the top players in NBA history.

These three words are incredibly similar, but it is worth noting that sounding similar doesn't mean that they mean similar things.

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What does it mean to ensure something?

To ensure something is to make sure it happens, such as by taking action or using authority.

Is it insure or ensure success?

The correct phrase is ensure success, meaning to make sure that something is successful. To insure is to take out an insurance policy on something or guarantee it through some other type of transaction, so you can’t insure success—at least not literally.


Hannah Skaggs

Along with Paige Pfeifer

Hannah, a writer and editor since 2017, specializes in clear and concise academic and business writing. She has mentored countless scholars and companies in writing authoritative and engaging content.

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