How does Viola react when Malvolio catches up to her and wishes to return the ring to her in Twelfth Night?

Viola's reaction when Malvolio returns the ring goes through a few stages. First, she is confused, as she does not recall leaving a ring behind. Then, she is offended by Malvolio's snobby manner, where he essentially tells her not to come back (though at this point, Malvolio and the other characters still think she is "Cesario").
Once Malvolo drops the ring and leaves, Viola tries to figure out why Olivia should send the ring back if "Cesario" did not bring it to her in the first place, and it is here that it dawns on Viola that Olivia might be infatuated with her alter ego. She suddenly recalls Olivia not being able to take her eyes off of her during their talk as well as Olivia having a hard time speaking from being so flustered.
Viola ultimately pities Olivia, since she is in love with a construct and not a real person. One might say Viola also relates to Olivia, since Viola is also harboring an unrequited love for Orsino.