What is the theme of my last duchess

What is the effect of narrator's word choice on the tone of this passage? the words "my heart shrank within itself" create a fearful tone. the words "wounded his fellow" develop a remorseful tone. the words "struck harsh upon my ears" suggest an irritated tone. the words "better-omened" set a hopeful tone. excerpt from "the cabuliwallah" by rabindranath tagore i was sitting in my study, looking through the accounts, when some one entered, saluting respectfully, and stood before me. it was rahmun the cabuliwallah. at first i did not recognise him. he had no bag, nor the long hair, nor the same vigour that he used to have. but he smiled, and i knew him again. "when did you come, rahmun? " i asked him. "last evening," he said, "i was released from jail." the words struck harsh upon my ears. i had never before talked with one who had wounded his fellow, and my heart shrank within itself when i realised this; for i felt that the day would have been better-omened had he not turned up.