Changing names to change morality

in dealing with a broker recommending mortgage on whether to disclose the best offer for the customer or the agent. Is it best to tell the buyer the best one available for them or is it best to tell the one from which the agent makes the most. The name has now in some instances become introducer rather than advisor so that people assuage their guilt about telling something that they may know or at least suspect is less than the best product for the client.