affirm

swear

To make a solemn commitment to perform an action or affirm the truth of a statement.

He swore to keep the secret.
Beginner
I swear I will help you.
Beginner
She swore on her life.
Beginner
Before testifying, witnesses must swear an oath to tell the whole truth.
Intermediate
The new citizens swore allegiance to their adopted country during the ceremony.
Intermediate
He swore to his family that he would never make that mistake again.
Intermediate
The legal system relies on individuals to swear to the veracity of their statements, underpinning the integrity of judicial proceedings.
Advanced
The ancient ritual required the initiates to swear a sacred vow, binding them to the order's principles.
Advanced
In a poignant moment, the protagonist swore an unshakeable oath of vengeance against those who wronged his family.
Advanced

swear(/swɛr/)

To declare solemnly and truthfully that something is the case.

I swear it's true.
Beginner
He swore he didn't do it.
Beginner
She swore she saw a ghost.
Beginner
I swear to you, I will finish this project on time.
Intermediate
The witness swore that her testimony was accurate.
Intermediate
He swore he would never betray his friends.
Intermediate
She swore an affidavit affirming the veracity of her statements.
Advanced
Despite the overwhelming evidence, he continued to swear his innocence.
Advanced
The ancient ritual required participants to swear an unbreakable vow.
Advanced