Use the sample I751 affidavit as an example. This affidavit is a contract between a sponsor and the U.S. Government.Completing and signing Form I-864 makes you the sponsor. An I130 affidavit is a written statement from friends, family members, or associates who can attest to the genuine nature of your marriage. Use this form to show they have adequate means of financial support and are not likely to rely on the US government for financial support.