In any instance where, in the opinion of the Council, the owner of any property which is assessed to defray any part of the cost of making any public improvement benefiting such property is unable to contribute toward the cost thereof because of poverty, the City may take from the owner a trust deed or assignment of the property so assessed, in lieu of the payment of such assessments in cash. Such trust deed shall not deprive the owner of such property of full right to use and occupy such property so long as he shall live and shall contain a clause to the effect that such deed shall cease to be effective upon the payment of the assessments which have accrued and become payable upon the property.