Translation

約束する / 誓う / 保証する

Meaning

To promise means to tell someone that you will definitely do something (or not do something) in the future. It is a commitment that creates an expectation of trust. 'I promise to call you.' 'She promised she would not tell anyone.' A 'promise' as a noun is the commitment itself. For Japanese learners: 約束 is very close to 'promise' in Japanese and carries the same weight of obligation. However, English distinguishes 'promise' (personal commitment) from 'vow' (solemn oath) and 'pledge' (formal commitment, often public).

Examples

• 秘密を守ると約束する。
  I promise to keep the secret.
• 彼女は二度と遅刻しないと約束した。
  She promised never to be late again.