How does the man rate his ability to play tennis in the conversation?

The man rates his ability to play tennis as "not very good," indicating a modest self-assessment of his skills. This phrase conveys a sense of humility and suggests that while he may have some level of proficiency, he does not consider himself highly skilled or an expert. It often reflects a realistic view of one's capabilities without overstating them. This choice aligns well with a conversation where someone may downplay their abilities, reflecting a typical attitude of those who are moderately skilled but not confident enough to claim a high level of expertise.