How does Viola act when Malvolio catches up to her and wishes to return the ring to her? What realization does Viola make once Malvolio exits? How does she feel about this?
When Malvolio finally catches up with Viola to "return" the ring she (as Cesario) left with Olivia--when of course she'd done no such thing--she (Viola) behaves as though she had offered the ring and that Olivia had graciously taken it. As soon as Malvolio leaves, though, she notes that she had left no ring with the lady at all, and realizes that her "outside have not charm'd her!" She remembers that Olivia had behaved strangely, and "did speak in starts, distractedly."
She feels sorry for Olivia, saying she'd be better off to "love a dream." She imagines this complex problem--that Orsino loves Olivia, Olivia loves Cesario (who is Viola), and Viola loves Orsino--has arisen because of the weakness of women. She decides that she can't figure out how to solve the problem. Time will tell.