When Father Guan heard Guan Miaoyan's words, he turned his gaze to Xue Fanxin and realized that she was only a fifteen or sixteen-year-old girl. Hence, he treated her as a child and asked in an overbearing tone, "How did you deceive my son to acknowledge you as his Mistress?"
From the looks of it, Father Guan was very dissatisfied with Guan Xiaoyan acknowledging a little girl as his Mistress.
"Father, what are you talking about? What deception? I was the one who pestered them, okay?" Guan Xiaoyan tried his best to explain for Xue Fanxin. "If not for them these two days, I would have been killed long ago. Master and Mistress are very capable. What's wrong with me taking them as my masters?"