promissory

adj. /ˈprɑːmɪsɔːri/ C2

许诺的；约定的

Containing or expressing a formal promise to do something.

仙境例句

The Knave signed a promissory note, promising to pay for all the tarts he ate.

红桃杰克签了一张欠条，答应为他吃掉的所有馅饼付钱。