Quote 1
"Dorian, Dorian," she cried, "before I knew you, acting was the one reality of my life. It was only in the theatre that I lived. I thought that it was all true. I was Rosalind one night and Portia the other. The joy of Beatrice was my joy, and the sorrows of Cordelia were mine also. I believed in everything. The common people who acted with me seemed to me to be godlike. The painted scenes were my world. I knew nothing but shadows, and I thought them real. You came -- oh, my beautiful love! -- and you freed my soul from prison. You taught me what reality really is. To-night, for the first time in my life, I saw through the hollowness, the sham, the silliness of the empty pageant in which I had always played. To-night, for the first time, I became conscious that the Romeo was hideous, and old, and painted, that the moonlight in the orchard was false, that the scenery was vulgar, and that the words I had to speak were unreal, were not my words, were not what I wanted to say. You had brought me something higher, something of which all art is but a reflection. You had made me understand what love really is. My love! My love! Prince Charming! Prince of life! I have grown sick of shadows. You are more to me than all art can ever be. What have I to do with the puppets of a play?" (7.15)
With Dorian's love, Sibyl has realized that the life she lived before was not, in fact, life at all. Art had been everything to her (as it is to a certain Basil Hallward), but now that she's found love, she realizes that it's no substitute for real life experience.
Quote 2
"You have spoiled the romance of my life. How little you can know of love, if you say it mars your art! Without your art, you are nothing. I would have made you famous, splendid, magnificent. The world would have worshipped you, and you would have borne my name. What are you now? A third-rate actress with a pretty face." (7.18)
It becomes clear that Dorian only valued Sybil as an aesthetic object. She was, to him, a living work of art, and, now that she can't act anymore, she's lost all of her value.
Quote 3
"Sibyl? Oh, she was so shy and so gentle. There is something of a child about her. Her eyes opened wide in exquisite wonder when I told her what I thought of her performance, and she seemed quite unconscious of her power. I think we were both rather nervous. The old Jew stood grinning at the doorway of the dusty greenroom, making elaborate speeches about us both, while we stood looking at each other like children. He would insist on calling me 'My Lord,' so I had to assure Sibyl that I was not anything of the kind. She said quite simply to me, 'You look more like a prince. I must call you Prince Charming.'" (4.11)
Sibyl's innocence, like Dorian's own, is what makes her so very appealing.