In T.N. there is new tenancy Act Tamil Nadu Regulation of Rights and Responsibilities of Landlords and Tenants Act, 2017 which is balanced between landlord and tenant and proceedings are very fast. Under the Act the tenant is bound to execute a tenancy agreement with landlord. Sent him a properly drafted tenancy agreement with terms you want. There is no restriction on amount of rent and duration of tenancy. If the tenant fails to sign the agreement you can submit the same to Rent Authority of the district who is deputy Collector of district, he will upload the agreement on the website of government and it shall be treated as executed between landlord and tenant. On failure of tenant to pay the mentioned rent, you can immediately seek his eviction by Rent Authority.