许诺 (xǔ nuò) is a formal, written-style verb meaning 'to promise' — to give one's word that something will be done or fulfilled. It combines 许 (xǔ), which means 'to permit' or 'to agree', and 诺 (nuò), meaning 'to assent' or 'a pledge'. Together, they emphasize a solemn, intentional commitment rather than a casual assurance. The word carries weight and sincerity, often implying moral or social responsibility.

This term appears frequently in literature, formal speeches, legal contexts, and serious interpersonal communication — for example, when someone vows to uphold a duty, honor a debt, or fulfill an obligation. It is less common in everyday spoken Chinese, where simpler verbs like 承诺 (chéng nuò) or 答应 (dā yìng) are preferred. While it can be used transitively (e.g., 许诺某事), it’s also commonly followed by a clause introduced by '了' or '过' to indicate completion or past commitment.