assure vs ensure

What is the difference?

definition: tell someone something positively to dispel any doubts
  1. Tony assured me that there was a supermarket in the village
  2. ‘I quite understand,’ Mrs Lewis assured her
  3. they assured him of their full confidence
reassure, convince, satisfy, persuade, guarantee, promise, tell
definition: make certain that (something) will occur or be the case
  1. the client must ensure that accurate records are kept
make sure, make certain, see to it

assure vs ensure

What's the difference between assure and ensure? Many people use these two verbs interchangeably as synonyms, as they both derive from similar linguistic backgrounds. In English, however, they are supposed to be used in different contexts. Keep reading, and we will explain the differences so you never have to use them incorrectly again!

1. assure


To assure was one of the first verbs in English to derive from the Latin word, "sēcūrus," meaning to be safe, secure, or free from care. However, modern-day definitions of assure are to give confidence, to reassure, or to get rid of doubts. You promise, persuade, or convince when you assure someone and give them confidence or trust in what you say.


Origin of assure

In Etymology, the study of Historical linguistics, the verb assure derives from many origins. The Old French assure root is "asseurer," which means to protect, reassure, or calm down.

Examples for assure

I can assure you that this medicine will help.

My boss assures me that I will get a promotion.

I assure you that I will arrive on time.

2. ensure


When we use to ensure, on the other hand, we express that something will or won't happen. The verb to ensure means to check, guarantee, or vouch.

check sign

Origin of ensure

The root word for ensure is from Old French. "en" means to make, and "seur" means sure in English. This makes "enseur."

Examples for ensure

We will do our best to ensure that other mistakes aren't made.

Ensure you get that work done soon as possible.

If you ensure us with the details, we can tell you how much it will be.

Takeaways - Tips

Check out these quick tips to further your knowledge.


Think of to assure as giving trust and assurance. Remember to assure is to remove doubts and concerns.


Ensure is a synonym for to check, vouch, or guarantee. Think of it as a promise or a way to say you will make sure that something happens.

Bottom Line

If you're ever in doubt, think about the message you want to get across. If you are trying to give someone confidence or calm them down, you most likely want to use assure. If you want to guarantee something, use ensure.


When to use assure?

When to use ensure?

How to remember assure vs. ensure?

Commonly Confusing Words

Spell checkers don't always have you covered. Sometimes your word might be spelled correctly, but it could be the wrong word. In English, there are lots of confusing terms that look alike but are spelled differently, and many terms that mean the same thing but are easily misused.

Here are the most commonly confusing word pairings, with definitions and examples of their usage.

Check it out!