Answer:
These lines develop the plot that Luciana had ulterior motives to inviting Rosaura to the party.
Explanation:
The given lines are stated by Señora. She is one of the main characters of the story. Her behavior with Rosaura is horrible. Rosaura was invited to the party just so she could help Senora. On the other hand, Rosaura thought of this invitation as a sign of good gesture from Luciana.