Real Dictionary

promise
verb: If you promise someone something, you tell them that you will definitely give it to them or make sure that they have it.
verb: If you promise that you will do something, you say to someone that you will definitely do it.

promise in American English
an oral or written agreement to do or not to do something; vow
to make a promise
intransitive verb: to afford ground for expectation
noun: a declaration that something will or will not be done, given, etc., by one
transitive verb: to engage or undertake by promise (usually used with an infinitive or a clause as object)

promise in British English
noun: an undertaking or assurance given by one person to another agreeing or guaranteeing to do or give something, or not to do or give something, in the future
verb: to give an assurance of (something to someone); undertake (to do something) in the future