Commissivum

Commissiva or commissive speech acts are speech acts in which a speaker undertakes to carry out a future action. Commissive speech acts are determined by commissive verbs: promise, vow, swear, threaten, etc.

Examples: "I will never lie to you again!" or "I'll try my best to be on time!".

See also

Speech Act Theory # Classification of Speech Acts (Searle)

Web links

Wiktionary: commissive  - explanations of meanings, word origins, synonyms, translations