When Dorian wakes later that day, he goes about his usual business—he peruses his mail (setting aside a letter from Henry, unopened), gets dressed, and has a pleasant breakfast.
During his meal, Dorian's eye falls upon the screen that hides the portrait. He worries that the frightening change he saw in it last night might still be there in the clear morning light. As soon as his valet leaves the room, Dorian locks the doors and takes another look at his picture.
His impression the night before was right—the portrait has changed. He can't understand or explain it: does the painting have some kind of link to his own soul? He's horrified.
Regarding his altered image, Dorian feels terrible about what he's done to Sibyl. He decides to go back to her and devote his life to loving her—the portrait's embodiment of his sins serves as a kind of conscience. He immediately sits down to write her a long, melodramatically passionate letter; when he's done, he already feels forgiven.
At that moment, Lord Henry shows up. He wants to make sure Dorian's not too worried about the whole Sibyl thing; Dorian tells him that he's not sorry for any of it, and that it's taught him more about himself. He announces that he wants to be good from now on to keep his soul from growing hideous, and says he'll start by marrying Sibyl Vane.
Henry is taken aback—it turns out that the letter he wrote to Dorian (the very one we saw the boy put aside unread) contains some terrible, terrible news: Sibyl Vane is dead.
Dorian is understandably distraught, but Henry mostly wants to make sure that Dorian's in the clear, and that he won't be scandalously involved in the death.
It turns out that Sybil almost certainly committed suicide by poison (ugh!). Dorian is incredibly upset, but Henry callously starts talking about the opera—he wants Dorian to come out with him and his sister.
Dorian can't get over the shock, and hashes out all of his feelings—he's guilty and sad and angry all at the same time. Henry convinces him that the whole Sibyl thing was a mistake to begin with, and that they would never have been happy had they gotten married.
Dorian is alarmed by the fact that he doesn't exactly feel this event as much as he should—rather, he's starting to look at it like the completion of a beautifully tragic work of art.
Henry seizes upon this moment of weakness to convince Dorian even more fully that this was how things had to play out; he even claims that Sibyl proved just how special she was by killing herself over Dorian. Wow, if that's not warped, we don't know what is.
Henry ends by claiming grandiosely that since Sybil never "really" lived, she didn't really die, either. This logic seems a little flawed to us, but Dorian buys it. He gives in to Henry's torrent of words, and agrees to go to the opera.
Once his friend leaves, Dorian takes another look at the portrait. The cruelty in the painted figure's face has a new meaning now—it's associated with Sibyl's death. He gets all emotional about the idea of Sibyl's tragic sacrifice (notably, he's no longer sad about the girl herself, but her abstraction).
Regarding the portrait, Dorian thinks for a moment that maybe he should pray to try and stop the weird, symbiotic relationship between his soul and the picture. He decides, however, that he should leave the portrait as it is, so he can watch what happens to his soul. All that matters to him is that his own physical beauty remains unmarred.