He had stayed at the Situ mansion waiting to profess his love for Yin Zhu, he wanted to tell her that for the sake of courting her, he was even willing to be the servant of the Situ family. In Master Chu's eyes as long as he was to show his sincerity, Yin Zhu would be moved. After all, a man lowering his dignity for a woman was rare and he had done it for her, Yin Zhu should have been touched!
In his high hopes, Master Chu completely forgot that the reason he was forced to work as a servant was because he was caught attending the banquet when he had no invitation. However, Master Chu had conveniently chosen to forget this small detail.
He just wanted to show Yin Zhu that he was the correct man for her and no one else could treat her better than him!