The speaker is someone who loves a young man deeply but struggles to show it. He once made her cry with careless words and stubbornness, but now she says she can't cry at all. The poem suggests the speaker is a parent or a similar caring figure, though it never says so directly. Her eyes are dry, yet they "ache with sorrow," which makes the grief feel stored up rather than gone.
What stands out is the gap between what she feels and what she says. She admits her "harsh tones and bitter words" give her away, so he hears anger instead of care. She prays he'll one day understand that she cares more than she lets on. She also believes he is gifted and deserves better, and she includes herself in that, writing that "we all do."
The mood is tired and sad, but not hopeless. She promises to stay until her body fails, and she holds onto the idea that someday she will reach him.