No such project shall be deemed a qualifying project for funding unless a user, tenant, lessee or sublessee entitled to revenues or receipts from the project shall secure for the project a letter of credit, policy of insurance, guaranty or other suitable security, issued by a creditworthy financial institution or surety, approved by the director of the state department of economic development, which approval shall not be unreasonably withheld, unconditionally guaranteeing payments of any bonds or other indebtedness issued to fund construction of the project.