Affirmative-negative questions are often used to introduce a rhetorical tone, particularly when introduced by phrases like 你说 nǐ shuō (lit. ‘What do you say to that?’):
Nǐ shuō zhè jiàn shì guài bú guài ？
Don’t you think this is strange?
Nǐ shuō tā zhè gè rén lì hài bú lì hài ？
She is really tough/formidable, isn’t she?/ Don’t you think she is really tough /formidable?
Nǐ shuō zhè zhǒng gōng zuò nán bú nán ？
This is a difficult job, isn’t it?/Don’t you think this is a difficult job?
 Yip, P. C., Rimmington, D., Xiaoming, Z., & Henson, R. (2009). Basic Chinese: a grammar and workbook. Taylor & Francis.