A commissive illocutionary point is the illocutionary point of a speaker committing to bring about the state of affairs described in the propositional content of the utterance.
According to certain analyses, a commissive illocutionary point is one of the five basic purposes that a speaker can have in making an utterance.
Searle, John, and Daniel Vanderveken. 1985.Foundations of illocutionary logic. Cambridge, England: Cambridge University.
Crystal, David. 1985.A dictionary of linguistics and phonetics. 2nd edition. New York: Basil Blackwell.