prepromise
/ˈprɛprəmɪs/Definitions
1. noun
A promise made before something else, especially a promise made before marriage.
“The pre-promise of lifelong love and commitment was a central aspect of their wedding vows.”
2. verb
To promise something before a certain time or event, especially before marriage.
“They prepromised to love and cherish each other for the rest of their lives.”