The monologue by the Duke clearly shows him as a cold, selfish, arrrogant, and extremely proud man. His attitude towards women is that they are chattels, property. This, of course, is especially true of his relationship with his deceased wife. She seems from his description to have been a kind and loving person, but he wanted her to be the mirror image of himself--cold, arrogant, and proud. It is interesting that he refers to the portrait of the wife he had murdered as "My last duchess." It hints that she was not his only duchess and that he might have had several wives before this "last" or "latest" one. Otherwise, it would have been more natural for him to say, "That's my first duchess." The phrase "My last duchess" also makes the reader fear for the future of the young woman he is presently negotiating to marry. He could have her killed too, if she doesn't measure up to his high standards; but it seems remotely possible that he is in the habit of marrying women for their dowries and then disposing of them in order to find his "next" duchess with another dowry. It almost seems as if his valuable art collection might have been paid for with dowries. The reader can only wonder what sort of an impression the Duke is making on his visitor and what report that representative will take back to the father of the girl the Duke is proposing to marry.