約束

The word "yakusoku" covers two distinct concepts in English: a "promise" (a commitment to do something) and an "appointment" (a scheduled meeting). While the word is the same, the social weight and the verbs used with it differ depending on the meaning.

When used as a "promise," it carries a moral or emotional weight. Breaking such a promise ("yakusoku o yaburu") is often seen as a breach of trust. In casual settings, especially among children, it is associated with "yubikiri" (pinky swear).

When used as an "appointment," it refers to a mutual agreement to meet. It is crucial to distinguish this from "yoyaku" (reservation). "Yakusoku" is used for people (e.g., meeting a friend or a business partner), whereas "yoyaku" is used for services or facilities (e.g., booking a hotel room, a restaurant table, or a doctor's appointment). Using "yakusoku" for a hotel room would sound unnatural to a native speaker.

In business contexts, while "yakusoku" is used, more formal terms like "yotei" (schedule/plan) or "shiteki" (appointment/designation) might be used depending on the level of formality, but "yakusoku" remains the most common term for general interpersonal agreements.