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Assure, Ensure & Insure

December 19, 2014

There are many commonly confused words in English, such as too/two/to, there/their/they're, your/you're, despite/although, lay/lieinquire/enquire, etc. Words get confused because they have similar sounds, spellings, and/or meanings. Tara, our head writer, recently asked for a post about the difference between assure and ensure so she could include it in a lesson. While we're at it, let's take a look at insure, too!

Assure, Ensure & Insure

Some would argue that these words are interchangeable since they can all be defined as "to make certain; to guarantee." However, most people would argue (and most dictionaries would corroborate) that they are used for different situations. I'd recommend teaching your students the most common uses (and differences) below.

Part of Speech: verb
Meaning: to tell someone that something will definitely happen
Pronunciation: /æ ˈʃʌr/ (ah-SHURE) or, when speaking quickly, /ə ˈʃʌr/ (uh-SHURE)
  • I can assure you that your package will arrive on time.
  • The teacher assured the students that the test would only cover chapters 1 and 2.
Teaching Tip: Look for a direct object that is a person.
Part of Speech: verb
Meaning: to guarantee that something will happen
Pronunciation: /ɛn ˈʃʌr/ (en-SHURE)
  • He took steps to ensure his gift would arrive before December 25.
  • Correcting homework as a class will ensure that your students have understood the previous day's lesson.
Teaching Tip: Look for a direct object that is not a person, or look for a noun clause instead of an object.
Part of Speech: verb
Meaning: to buy insurance for something (see the definition for insurance below)
Pronunciation: /ɪn ˈʃʌr/ (in-SHURE)
  • Do you want to insure your package against damage or theft?
  • I insured my car for the maximum amount yesterday, so now I'm broke.
Teaching Tip: Insure is most commonly used for legal and financial purposes. Look for a direct object that is a thing, not a person.

Teaching Tip

I came across a great teaching tip from Charles Carson to help your students remember these terms! (I found this tip on Grammar Girl's website in a post called Assure Versus Ensure Versus Insure.) Students appreciate good memory tricks!

"…use assure for things that are alive (remember that a is for alive), ensure to guarantee events and conditions (remember those two e's at the end of guarantee), and insure for all of the above in financial contexts (remember the i is for income)."

Assurance & Insurance

How about the noun forms? Ensure doesn't have one, so we don't have to worry about that. And assurance and insurance have quite different meanings, so they are easier for students to learn than the verb forms.

Part of Speech: noun
Meaning: the state of being sure about something
Pronunciation: /æ ˈʃʌ ˌræns/ (ah-SHU-ranse) or, when speaking quickly, /ə ˈʃʌ ˌrəns/ (uh-SHUH-rinse)
Example: You say the package will arrive on time, but what assurance do I have? It was two weeks late last time.
Part of Speech: noun
Meaning: a policy/agreement where payments are made to protect something against future loss or damage
Pronunciation: /ɪn ˈʃʌ ˌræns/ (in-SHU-ranse)
Example: Most people buy car insurance, home insurance, and life insurance to protect themselves and their families.


Show your students the word assure in context in the description of Lesson 1, A Recipe for Disaster, of our brand new Detective Series 2, False Alarm. Did you notice that a lot of the examples above involved sending packages by mail or courier? With Christmas right around the corner, you could naturally use these terms in context at this time of year.

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Comments (4)

Judith W.(Teacher)

My students are Hispanic and I think this lesson will be important for them to learn.

Reply to Comment

Tanya Trusler(Author)

Great to hear, Judy! I agree that Hispanic students especially would benefit from the pronunciation tips for these words.

David (Guest)

Not everyone on the internet is American! In Britain, you never see INSURE used to mean ENSURE, whereas in the US it is common. Ensure is exclusively used to mean 'make certain' and INSURE is exclusively used to refer to insurance.

Reply to Comment

Tanya Trusler(Author)

Hi David,

In my post, you'll see that the North American usage stated in most dictionaries agrees with the UK usage you mention:

Ensure is a verb that means to guarantee that something will happen.
Insure is a verb that means to buy insurance for something.

I've read that some people use them interchangeably, but here in Canada, I've never heard 'insure' used to mean 'make certain.' I don't believe it's common in the US either, but it may depend on where you live.

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