Final answer:
Marcia's sentiment toward the person being referred to is one of gladness, as indicated by her expression of relief that he does not know her or her associates.
Step-by-step explanation:
When Marcia says, "Well, I'm glad he doesn't know us," she is expressing a sense of relief. This indicates that Marcia's sentiment toward the person being referred to is one of gladness, as she does not want that person to be acquainted with her or the group she is a part of. This sentiment likely stems from a desire to remain disconnected from whatever associations or complications knowing that person could bring.
Understanding Marcia's sentiment is key for interpreting interactions between characters in literature. It provides insight into her feelings and motives within the narrative. The act of being glad implies a positive feeling that is opposite to being upset, indifferent, or unclear about a situation.