Maria's poem is about hiding pain behind a smile. The speaker repeats the same instruction to herself, "I tell myself to smile," and each time she gives a different reason. First, the pain is deep inside, so no one can see it. Second, she believes nobody would care about it anyway. Third, crying simply isn't worth the effort.
The reasons grow sadder as the poem goes on. It starts with concealment, moves to loneliness, and ends with a kind of weary giving up. The smile isn't a sign of happiness. It works more like a mask she puts on every day, almost as an order she gives herself.
The repetition makes the mood feel heavy and tired, as if she has said these words many times before. The title, "SMILE....", with its trailing dots, seems to hang in the air, suggesting something unfinished or unspoken. The poem is quiet, but it leaves a lingering sense of isolation.