Affidavit definition: . See examples of AFFIDAVIT used in a sentence.A document prepared for filing with the Register of Deeds or Secretary of State indicating that personal property or fixtures is encumbered with a debt. A written statement that someone makes after promising officially to tell the truth. An affidavit can be used as proof in a law court. Affidavit – Proof of Financial Responsibility for Employer or Rental Vehicles – State Form 55434. These rules are intended to promote a just determination of every criminal proceeding. They are to be construed to secure simplicity in procedure. Please read the following instructions carefully before completing and submitting the Statement of. Financial Support to Wayne State University.