vow
Definitions
A solemn promise or pledge to perform a specific act or behave in a specified manner.
A formal declaration or assertion, often made to a deity or in a religious context.
To dedicate or consecrate someone or something to a service or goal.
Examples
The couple made a solemn vow to support each other through every challenge.
He took a vow of silence to focus entirely on his meditation practice.
The politician made a public vow to reduce taxes within the first year of his term.