A second chance to secure your dream home. Helping you qualify for the rental you want, while giving property managers protection against defaults.A guarantor guarantees the lease in case the tenant doesn't qualify on their own for a New York City apartment. Co-signers will also need to fill out a Rental Guaranty Addendum form. Com or ask your property manager about Leap. Unlike the applicant, a lease guarantor's requirements are very different. A lease co-signer merely guarantees that if the tenant doesn't pay the rent, the guarantor will pay it. We guarantee leases so you can qualify, giving landlords more confidence renting to you. Save money at move‑in. A guarantor for an apartment will cosign a lease and assume financial responsibility in case a tenant can't afford to pay rent.