約束 (yakusoku) means “promise” | MotiTan Japanese Dictionary

More examples

お母さんに宿題をすると約束しました。o haha sa n ni shuku dai o su ru to yaku soku shi ma shi ta

I promised my mom that I would do my homework.

困ったときは、その約束を思い出してください。koma tta to ki wa so no yaku soku o omo i da shi te ku da sa i

Please remember the promise when you are in trouble.

約束 (yakusoku) presents a future action as something people have mutually fixed and are expected to honor.

予約yoyaku: A plan made in advance to secure a service, place, or time.
誓いchikai: A serious promise that shows firm personal resolve.

互いに守るべきことを前もって取り決めること。taga i ni mamo ru be ki ko to o mae mo tte to ri ki me ru ko to

約束 (yakusoku) is a Sino-Japanese compound of 約 (yaku, "agreement") and 束 (soku, "binding"), describing an agreement that binds the parties.

Unlike English promise, 約束 (yakusoku) is commonly used for a scheduled meeting as well as for a commitment to do something.