What is Affidare?

Legal Definition
To plight one's faith, or give fealty, i. e. fidelity by making oath, &c. Cunn. Dict. h. t.
-- Bouviers Law Dictionary
Legal Definition
To swear faith to; to pledge one's faith or do fealty by making oath. Cowell.
-- Black's Law Dictionary
Legal Definition
To swear.
-- Ballentine's Law Dictionary