Each guarantor must submit and execute a separate. Lease Guaranty, unless guarantors are married.1. Begin with the landlord's and tenant's names and contact information. A guarantor guarantees the lease in case the tenant doesn't qualify on their own for a New York City apartment. A lease guaranty is an agreement that offers an added layer of security for property owners. Day In The Life Of A Property Manager. Bexar County real estate attorney Geoff Mayfield represents residential and commercial landlords in a range of real estate matters.