Assure means to tell another person something to remove doubt or anxiety.
▶️ I was afraid we’d miss the flight, but my husband assured me we’d get to the
airport in time.
▶️ I assure you that the water here is perfectly safe to drink.
After assure, we always have a person: assure you, assure him/her, etc.
Ensure is something you do to guarantee a specific result.
▶️ We ordered ten pizzas to ensure that there would be enough food for
everybody.
▶️ Please send the document by express mail to ensure that it arrives on time.
Insure (spelled with an “I”) is when you get a financial plan to pay for any damage
or loss to a person or thing. This is related to the word insurance, such as health
insurance, car insurance, etc.
▶️ Our house is insured against fires, floods, and theft.