assure

verb

as·​sure ə-ˈshu̇r 

assured; assuring

transitive verb

1

: to make sure or certain : convince

glancing back to assure himself no one was following

2

: to inform positively

I assure you that we can do it.

3

: to make certain the coming or attainment of : guarantee

worked hard to assure accuracy

4

: to make safe (as from risks or against overthrow) : insure

assured the security of the country

5

: to give confidence to

And hereby we know that we are of the truth, and shall assure our hearts …

—1 John 3:19 (King James Version)

Synonyms

• reassure
• comfort
• soothe

Choose the Right Synonym for assure

ensure, insure, assure, secure mean to make a thing or person sure.

ensure, insure, and assure are interchangeable in many contexts where they indicate the making certain or inevitable of an outcome, but ensure may imply a virtual guarantee

the government has ensured the safety of the refugees

, while insure sometimes stresses the taking of necessary measures beforehand

careful planning should insure the success of the party

, and assure distinctively implies the removal of doubt and suspense from a person's mind.

I assure you that no harm will be done

secure implies action taken to guard against attack or loss.

sent reinforcements to secure their position

Examples of assure in a Sentence

I can assure you that you won't be disappointed.

a minister choosing just the right words to assure the grieving parents of the fallen soldier

Recent Examples on the Web

Just hours later, however, the former pop star assured fans that the Inter Miami CF co-owner was well on the road to recovery and already back in the vegetable patch! —Clare Fisher, People.com, 30 June 2025

To complete his scenes, production called upon various doubles, CGI, and even had the help of Walker's brothers to assure a close physical resemblance. —Shania Russell, EW.com, 29 June 2025

Google clarified this to assure users that this is about giving users more control over their data, not less. —Zak Doffman, Forbes.com, 29 June 2025

Chinese President Xi Jinping has made attempts to strengthen trade relations with other countries in recent months, assuring the world of its stability as a trading partner in contrast with the U.S. —Miranda Jeyaretnam, Time, 27 June 2025

Word History

Etymology

Middle English, from Anglo-French asseurer, assurer, from Medieval Latin assecurare, from Latin ad- + securus secure

First Known Use

14th century, in the meaning defined at sense 4

Phrases Containing assure

• assure oneself

Rhymes for assure

• abjure
• adjure
• allure
• brochure
• cocksure
• coiffure
• contour
• couture
• demure
• detour
• endure
• ensure

Kids Definition

assure

verb

as·​sure ə-ˈshu̇(ə)r 

assured; assuring

1

: to provide a guarantee of

assure security

2

: to give words of comfort or confidence to : reassure

tried to assure the worried children

3

: to cause to be sure or certain

assure himself that the door was locked

4

: to inform positively

can assure you of her dependability

Legal Definition

assure

transitive verb

as·​sure

assured; assuring

1

chiefly British : insure

2

a

: to inform positively

the seller assured the buyer of his honesty

b

: to provide a guarantee of