Earlier, when Li Xue was in the Western Arcade, Wen Sying was also there. She didn't plan to follow her and get herself insulted again, so she avoided her. But when saw her walking out in an exaggerated state, her curiosity took her hard, making her go closer to hear more about it.
Though she has missed her conversation over the call, she has well heard her talks with Feng Yi Lan. And the moment she heard it she made the plan to expose Li Xue in her identity as a mother.
Even though her comeback was successful, if her secret of being a mother comes out at the moment, everything will be ruined. And that was exactly her plan. But she didn't know that once again, Li Xue would be coming out lucky in saving herself.