what do the parting words of the poet and her smile signify?

The speaker realizes the agedness of her mother. She fears the loss of her mother which is a fear harbored in almost every child. Even earlier she had noticed the corpse like attributes of her mother and shuddering at the thought diverted her attention to young blossoms and blooming children. It is very difficult for the speaker to internalize the fact that her mother might not live for long anymore. When she looks at her mother from the terminal she finally accepts the truth about her mother’s agedness, senility and mortality. Her last words are desperately hopeful and yet full of uncertainty. She realizes that her last words are not much reassuring even to herself but she tries to hide her pain and fears and smiles instead of mourning about the impending separation and demise.