as·​sure | \ə-ˈshu̇r \
assured; assuring

Definition of assure 

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)

Keep scrolling for more

Synonyms & Antonyms for assure


cheer, comfort, console, reassure, solace, soothe


distress, torment, torture, trouble

Visit the Thesaurus for More 

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

Now, The Wife assures me this cable Ouroboros calls itself Xfinity. Jon Brodkin, Ars Technica, "Negotiating with ISPs: Don’t accept broadband price hikes without a fight," 9 Nov. 2018 Apple Watch owners can rest assured that today’s update is specifically built not to brick their devices. Dami Lee, The Verge, "watchOS 5.1.1 is out now, and it will no longer brick your Apple Watch," 5 Nov. 2018 Though she's been in the cookbook game for the better part of two decades, Garten assures that she hasn't slacked on this installment's recipes. Chloe Foussianes, Town & Country, "Why Barefoot Contessa's Ina Garten Doesn't Drink While She Cooks," 16 Oct. 2018 First of all, Dr. Shirazian assures us that these bumps are completely normal. Yerin Kim, Seventeen, "Why Are There Bumps on My Nipples?," 11 Oct. 2018 Royal reporter Victoria Arbiter assures there's no bad blood between Eugenie and her aunt after the decision. Rachel Epstein, Marie Claire, "Camilla Parker-Bowles Is Skipping Princess Eugenie's Wedding," 8 Oct. 2018 Luka Modric's goal in the 80th minute put Croatia up 2-0 and virtually assured victory. Jim Reineking, USA TODAY, "Top 10 World Cup moments: Heroics from Cristiano Ronaldo, Lionel Messi, Hirving Lozano," 29 June 2018 The state’s unusual primary system, which allows the top two candidates to advance regardless of party affiliation, virtually assures that the two Democrats will continue their fight beyond Tuesday’s primary. Geoff Mulvihill, The Seattle Times, "State attorney general races gain attention in Trump era," 2 June 2018 That assures him of a favorable ballot position that by itself can often determine New Jersey primary elections. Jonathan Tamari,, "Center and left clash in key South Jersey House race," 24 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'assure.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of assure

14th century, in the meaning defined at sense 4

History and Etymology for assure

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

Keep scrolling for more

Learn More about assure

Statistics for assure

Last Updated

5 Dec 2018

Look-up Popularity

Time Traveler for assure

The first known use of assure was in the 14th century

See more words from the same century

Keep scrolling for more

More Definitions for assure



English Language Learners Definition of assure

: to make (something) certain

: to tell someone in a very strong and definite way that something will happen or that something is true


as·​sure | \ə-ˈshu̇r \
assured; assuring

Kids Definition of assure

1 : to give certainty, confidence, or comfort to He assured the children all was well. She assured herself that the doors were locked.

2 : to inform positively I assure you that you won't be disappointed.

3 : to provide a guarantee of assure their safety Hard work assures success.

assured; assuring

Legal Definition of assure 

1 chiefly British : insure

2a : to inform positively the seller assured the buyer of his honesty

b : to provide a guarantee of

Keep scrolling for more

More from Merriam-Webster on assure

Rhyming Dictionary: Words that rhyme with assure

Thesaurus: All synonyms and antonyms for assure

Spanish Central: Translation of assure

Nglish: Translation of assure for Spanish Speakers

Britannica English: Translation of assure for Arabic Speakers

Comments on assure

What made you want to look up assure? Please tell us where you read or heard it (including the quote, if possible).


having a pattern of small flowers

Get Word of the Day daily email!

Test Your Vocabulary

Find the Cousins

  • a-large-tree-with-many-branches
  • Which pair shares a common word ancestor?
True or False

Test your knowledge - and maybe learn something along the way.

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!