An Lin had actually thought of a decent plan.
In order to ascertain whether Bai Yao was being forced into the wedding or not, the best way to do so would be to observe her in secret.
They could then observe what her emotional state was like prior to her wedding ceremony.
If she was filled with elation and joy, then this was most likely a wedding forged on the basis of mutual love. But if she was extremely distressed and distraught the entire time, then there was a good chance that she had been forced into the marriage.
After hearing An Lin's plan, Xiao Chou engaged in a bout of intense internal conflict before nodding with difficulty and agreeing to this course of action.
Even though he was very confident in Bai Yao's feelings toward him, it was still important to verify these things. At the very least, he needed to have An Lin, Tina, and Da Bai convinced as this would be of vital importance to the rest of the operation.