verb
aver
uh-VUR/əˈvɜːr/
To state confidently that something is true.
The witness avers that her statement is true despite skeptical questioning.

Etymology
The “to” and “true” elements are traced through a reconstructed verb meaning “make true” or “prove.” From verifying truth, the sense developed into confidently asserting it.
More examples
- The researchers aver that their findings support the theory.
- She averred that she had never signed the agreement.
- He continues to aver his innocence.
Forms
aver · avers · averred · averring
averment noun — A confident statement that something is true.