ESEN
Which one to use?Intermediateverbverb
AssurevsEnsure
'Assure' means to tell someone with confidence that something is true; 'ensure' means to take steps to make certain something happens.
Side-by-side comparison
Assure
verb"Assure" is directed at a person: you reassure them and give them certainty about something. "I assure you it's safe" means I promise you it is safe.
I can assure you that the data was reviewed by three independent teams before publication.
She assured the investors that the project would be completed within the original budget.
He called to assure his family that he had arrived safely after the long drive.
Ensure
verb"Ensure" is directed at an outcome: you guarantee that something happens. There is no person to reassure; there is a situation to secure.
Please double-check the report to ensure there are no errors before it goes to the client.
The new protocol was designed to ensure patient confidentiality at every stage of treatment.
Back up your files regularly to ensure you never lose critical work.
Common mistake
- •"Please ensure the client that we are on track" is wrong: the client is a person, so you "assure" them.
- •"Ensure" goes with results and situations: "ensure the quality", "ensure the deadline is met".
Trick to remember it
- •Are you telling a person something to remove their worry? "Assure".
- •Are you taking concrete steps to guarantee an outcome? "Ensure".
Quick rule
- •"Assure" = reassure a person.
- •"Ensure" = guarantee a result or situation through action.
Did you know?
There is a third word that causes extra confusion in financial contexts: "insure", to protect against risk with an insurance policy ("insure your car", "insure a shipment"). The full distinction: assure = put a person at ease; ensure = guarantee a result; insure = take out a financial policy. This trio appears frequently on advanced English exams (IELTS, TOEFL, Cambridge C1/C2) as a test of precision.
Practise what you learned
Exercise 1 · Pick the right one
I called my mum to _____ her that I had arrived safely. She was very worried.
Exercise 2 · Pick the right one
Double-check the dates to _____ there are no mistakes before you send it.
Exercise 3 · Form the word
Related word pairs
AcceptvsExcept
One means to receive or agree to something, the other means to exclude or not include.
AdvicevsAdvise
'Advice' is the guidance you receive (noun); 'advise' is the act of giving that guidance (verb).
AffectvsEffect
'Affect' is the verb meaning to influence something; 'effect' is the noun meaning result or consequence.
AislevsIsle
'Aisle' is the walkway between rows of seats or shelves; 'isle' is a small island.
Bryan López
Founder of SpeakUP Academy