Isn't the whole basis of a relationship honesty and trust? (eharmony.co.uk)
Or it can be a like a relationship where both people are invested, only they know the ultimate basis of the relationship. (beyondblackwhite.com)
The rental agreement or lease that you and your tenant sign sets out the contractual basis of your relationship with the tenant, and is full of crucial business details, such as how long the tenant can occupy the rental and the amount of the rent. (nolo.com)