assure

/əˈʃʊər/

/əˈʃɔ/

Other forms: assured; assuring; assures

If you assure your boss that you’ll finish your project by Tuesday, you are making a promise or commitment to have it done by Tuesday.

The verbs insure and ensure look and sound like assure but they aren't synonyms. There is some overlap in meaning — all of them can mean “to make secure or certain” — but assure is generally used in situations when you are referring to a person: “I assure you that I haven’t forgotten about driving you to the airport,” or “He called his mother to assure her that everything will be fine.”

Definitions of assure

1. verb

   inform positively and with certainty and confidence
   synonyms: tell

   type of:

   affirm, assert, aver, avow, swan, swear, verify

   declare or affirm solemnly and formally as true
2. verb

   assure somebody of the truth of something with the intention of giving the listener confidence
   “I assured him that traveling to Cambodia was safe”

   types:

   reassure

   give or restore confidence in; cause to feel sure or certain

   type of:

   persuade

   cause somebody to adopt a certain position, belief, or course of action; twist somebody's arm
3. verb

   cause to feel sure; give reassurance to
   synonyms: reassure

   type of:

   calm, calm down, lull, quiet, quieten, still, tranquilize, tranquillise, tranquillize

   make calm or still
4. verb

   be careful or certain to do something; make certain of something
   synonyms: ascertain, check, control, ensure, insure, see, see to it

   check, check off, mark, mark off, tick, tick off

   put a check mark on or near or next to

   check

   verify by consulting a source or authority

   ascertain, check, determine, find out, learn, see, watch

   find out, learn, or determine with certainty, usually by making an inquiry or other effort

   control, verify

   check or regulate (a scientific experiment) by conducting a parallel experiment or comparing with another standard

   types:

   proof, proofread

   read for errors

   control

   verify by using a duplicate register for comparison

   double-check

   check once more to be absolutely sure

   cross-check

   check out conflicting sources; crosscheck facts, for example

   cinch

   make sure of

   card

   ask someone for identification to determine whether he or she is old enough to consume liquor

   spot-check

   pick out random samples for examination in order to ensure high quality

   cover

   maintain a check on; especially by patrolling

   type of:

   verify

   confirm the truth of
5. verb

   make certain of
   synonyms: ensure, guarantee, insure, secure

   guarantee, vouch

   give surety or assume responsibility

   types:

   doom

   make certain of the failure or destruction of

   make

   assure the success of
6. verb

   make a promise or commitment
   synonyms: promise

   types:

   pledge, plight

   promise solemnly and formally

   swear off

   promise to abstain from

   contract, undertake

   enter into a contractual arrangement

   guarantee, undertake

   promise to do or accomplish

   vow

   make a vow; promise

   stipulate

   make an oral contract or agreement in the verbal form of question and answer that is necessary to give it legal force

   sign

   be engaged by a written agreement

   subvent, subvention, underwrite

   guarantee financial support of

   guarantee, vouch

   give surety or assume responsibility

   condition, qualify, specify, stipulate

   specify as a condition or requirement in a contract or agreement; make an express demand or provision in an agreement

   covenant

   enter into a covenant or formal agreement

   lease, rent

   let for money

   charter, hire, lease, rent

   hold under a lease or rental agreement; of goods and services

   covenant

   enter into a covenant

   type of:

   declare

   state emphatically and authoritatively