Answer:
The reaper in the poem is not yearning for anything in particular. Instead, the speaker of the poem is watching the reaper and pondering her state of mind.
Step-by-step explanation:
The speaker of the poem notes that the reaper is singing her song with so much emotion, and he wonders what she could be feeling.
The speaker imagines that perhaps the reaper is yearning for something, but this is never explicitly stated.