Imagine you are the Count's representative in Robert Browning's "My Last Duchess." Having met the Duke and listened to his story about his first...

My first instinct would be to warn the Count to take his daughter and run!  This dramatic monologue that the Duke has with the Count's representative sounds like a thinly veiled warning of what he does when a woman displeases him.  As an aristocrat, the Duke surrounds himself with the finer things in life, and he expects perfection in a wife. He openly says that he refuses to stoop to the level of having to tell his wife how she should change for him, but if he did, he would say, "Just this / Or that in you disgusts me."  He is clearly a jealous man who wants complete control of a woman.  She is not to smile at others nor even look at them.  She shouldn't even let joy show on her face for anything other than him. His last wife "had / A heart...too soon made glad," and so, according to the Duke, "I gave commands; / Then all smiles stopped together."  Spoken looking at the portrait of his dead wife, it is a chilling warning.

As if that weren't enough, I would be further alarmed by the issue the Duke makes about the dowry the Count is to pay him. Although he apparently did not suggest a high amount to the Count (it seems he would not stoop to this, either), he wants the message sent that he expects a generous amount.  It's all about the money and control; the woman is simply an object of material value, to be molded and displayed as a prize, much like the bronze statue of Neptune the Duke brags of after dismissing the painting of his dead wife. Certainly the Count should be warned about what kind of man he is giving his daughter over to.

As I said, warning the Count would be my first instinct.  On closer inspection, however, this is not a chance conversation.  The Duke clearly intends for the representative to relay his messages to the Count, and perhaps the Count is downstairs waiting for the message. This poor representative must carefully weigh his words, to convey the message as diplomatically as possible. After all, the Count is agreeable to basically selling his daughter, as was customary for those of wealth during the period. So what would be the best course of action? To pass the information along to the Count, who is hopefully a good enough man to take his daughter and run!