Which line in this song from act ii, scene iii, of twelfth night illustrates that the song is about unrequited love?

The line that the song from ct ii, scene iii, of twelfth night illustrates that the song is about unrequited love is "As I remember the song about unrequited love begins in scene IV. It begins with words: "Come away, come away, death . . ." Feste sings another exceptionally dismal love tune and, a short time later, Orsino orders Cesario to go to Olivia once more, arguing Orsino's adoration to her.

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