Overall, the guarantor is applying for the apartment and must fill out a rental application, just like the tenant. Fill out the lease guaranty application online and send us your paperwork.1. You can get a third party to guarantee your lease. The guarantor must have a verifiable gross income of 4 times the monthly rent and have an acceptable VantageScore. Com or ask your property manager about Leap. A second chance to secure your dream home. Helping you qualify for the rental you want, while giving property managers protection against defaults. Landlords may require a lease guarantor to earn 40x90x the monthly rent in annual income to qualify. What is a Lease Guarantor? A lease guarantor is an individual who accepts financial responsibility if a tenant defaults on the lease agreement.