A "sworn statement" is a written or spoken declaration given under oath, confirming that the information provided is true to the best of someone's knowledge. It is legally binding and can be used as evidence in a court of law. Full definition
The police have sworn statements from the alleged victims. (si.com)
Two of the pastors later signed sworn statements saying they did not know about the letter or consent to have their names attached to it. (syracuse.com)
Or maybe you need someone to sign a formal sworn statement for you. (rocketlawyer.com)