Insure vs Ensure vs Assure

Insure and ensure are often interchangeable, but occasionally there is a small difference in meaning.  I have provided examples to ensure your understanding.


Insure, verb:  ɪnˈʃʊər, -ˈʃɜr

Insure can be done to a person, place, or thing, but often it is reserved for limiting financial liability, usually by obtaining an insurance policy. James wondered if the caterers were insured against loss.

You can remember that we take out insurance to protect our income if we become unemployed, disabled, or injured in an accident. Both insure and income begin with -in. –

  • To buy insurance for something (such as property or health): We insured our house against fire and flood.  He insured his boat.
  • To provide insurance for something (such as property or heath): This policy will insure your car against theft. I found a company that will insure my car for less than I’ve been paying.
  • To guarantee or protect against loss or harm: We hope that careful planning will insure success. Despite all of our planning, we can’t insure against bad weather.

Ensure, verb: ɛnˈʃʊər

Ensure is something you do to guarantee an event or condition. To ensure there’d be enough food, Sofia ordered twice as much as last year.

You can remember that guarantee has those two e’s on the end to help you remember that to ensure (with an e) is to guarantee something.

  • To secure, guarantee or promise: This ticket will ensure you a seat on the train. The government has ensured the safety of the refugees.
  • To make sure or certain: We are doing all we can to ensure the success of our business.
  • To make secure or safe:  Endangered animals are protected to ensure their survival.

Assure, verb: əˈʃʊər, əˈʃɜr

Assure is something you do to a person, a group of people, or an animal to remove doubt or anxiety. They assured us they’d come to the party early.

You can remember that assure can only be used with things that are alive (and both assure and alive start with a). Only things that are alive can feel doubt or anxiety, so only they can be assured.

  • To declare or state with confidence: I assure you that I will drive safely.  She assured us that everything would be all right.
  • To cause to know surely: He looked back to assure himself that no one was following him.
  • To promise or guarantee: He was assured a job in the spring. They assured us they would come.

Sources: Grammar Girl,, Merriam-Webster