Upon learning that the Cui family had not given up and would soon come to propose marriage formally, Mo Yan was not really worried. When that day came, she would just tell the Cui family the truth, that she was already engaged. The Cui family wouldn't break up someone's marriage, and even if they were willing to, they would have to see if she and Xiao Ruiyuan would agree.
She had not made it clear to the matchmaker earlier, thinking that a simple reason like mismatched social status would be enough to refuse the match; otherwise, she would have told the real situation earlier and wouldn't have let the Cui family fixate on her.