The Oxford Thesaurus An A-Z Dictionary of Synonyms - assurev.

1) secure, stabilize, settle, establish, confirm, certify, warrant, guarantee, ensure, be confident of, make or be sure or certain: Force, fear, and the multitude of his guard do less to assure the estate of a prince than the good will of his subjects. 2) encourage, inspirit, reassure, hearten: Your humanity assures us and gives us strength. 3) convince, persuade, reassure, make (someone) certain; ensure: What can I do to assure you of my love? 4 assert, state, asseverate, promise: I assure you that we shall do everything possible to find your dog.