Definition of Firmly
A statement that an affiant "firmly believes” the contents of the affidavit imports a strong or high degree of belief, and is equivalent to saying that he "verily” believes it. The operative words in a bond or recognizance, that the obligor is held and "firmly bound,” are equivalent to an acknowledgment of indebtedness and promise to pay.
That's the definition of Firmly in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.