Soju's short poem starts with a hopeful idea: people who hurt us might one day become better. But the poem quickly turns that hope into something painful. The sadness comes in the last lines, where the speaker points out that you will actually see the change you once longed for. It sounds like good news, so the sadness may seem strange at first.
The poem seems to suggest that the change arrives too late, or arrives for someone else. Maybe the person is kinder now, but only after the damage is done, or only toward new people. Seeing it makes the old hurt feel more unfair, because it proves the change was possible all along.
The mood is quiet, wistful and a little bitter. The speaker doesn't shout or accuse. The plain, calm wording makes the ache feel more real, like someone who has had a long time to think it over and still can't find peace.