WordWeb Online

1. Make certain in the future
   "Preparation will assure success!";
   - guarantee, ensure, insure, secure
    
2. Inform positively and with certainty and confidence
   "I assure you that man is a crook!";
   - tell
    
3. Tell someone the truth of something with the intention of giving the listener confidence
   "I assured him that travelling to Cambodia was safe"
    
4. Be careful or certain to do something; make certain of something
   "assure that the curtains are closed";
   - see, check, insure, see to it, ensure, control, ascertain
    
5. Make a commitment to do (or not to do) something in the future
   - promise

Derived forms: assured, assures, assuring

Type of: affirm, assert, aver, avow, declare, persuade, pronounce, swear, verify