Why does Esperanza decide to hold Silvia's hand, no matter how she feels about it?

When Silvia offers her hand, Esperanza remembers her mother's kindness to the peasant girl on the train, and she also remembers how disappointed Mama was with her own treatment of the little girl. Thus,vshe reasons how hard it must be to stay clean in such a dirty place, and she accepts the little Silvia's hand.