What is the verb for definitely?

There isn't a single verb that directly translates to "definitely". However, you can use various verbs depending on the context and what you want to emphasize. Here are some options:

To confirm:

* Affirm: "I affirm that I will be there."

* Assert: "I assert my right to privacy."

* Declare: "He declared his love for her."

* Guarantee: "I guarantee you'll enjoy the show."

* Promise: "I promise to call you later."

To express certainty:

* Know: "I know that I'm right."

* Believe: "I believe in you."

* Be sure: "I am sure about this decision."

* Be certain: "I am certain of her innocence."

* Be convinced: "I am convinced that it's true."

To express strong intention:

* Intend: "I intend to finish this project by Friday."

* Plan: "We plan to go on vacation next month."

* Decide: "I have decided to move to a new city."

* Determine: "She determined to overcome her fears."

The best verb to use will depend on the specific context and what you are trying to convey.