assure is on the Academic Word List.

Pronunciation change

Verb change

Plain form
assure

Third-person singular
assures

Past tense
assured

Past participle
assured

Present participle
assuring

  1. (transitive) If you assure somebody about something, you tell them not to worry because the thing you say is true.
    The doctor assured me that he would be OK.
    He certainly won't be boring; I can assure you of that.
  2. (transitive) If   assures that   happens,   makes it certain that   happens.
    You need to begin now to assure that the everything is ready in January.

Related words change