It is up to you and your potential tenant to decide who is the applicant filling out the rental application and who will sign the lease as a tenant. You do not have control over who comes in after the tenancy commences, as those people would be the tenant’s guests and therefore, the tenant’s problem. If the tenant named in the lease ends up not paying the whole rent or her guests/roommates cause problems like noise disturbances or damages, you would simply begin the eviction procedure against the tenant and try to prove your case at the Landlord and Tenant Board.