If Phoenix Si wanted to hide something from someone beside her, that person definitely wouldn't find out.
However, she didn't care if the other party knew or not. Or rather, if she deliberately let the other party discover it, then it was only a matter of time before the other party discovered it.
Yu Xi had long noticed that Si Huang had intentionally revealed something to him, but he did not say it explicitly. Whether he was willing to discover it or not depended on his own plans.
For example, he found out that Si Huang was not just a celebrity. He could kill people, he could do big things related to the country, he had connections with foreign nobles, and he had participated in several terrorist incidents.
As time passed, he slowly accepted these things. Yu Xi thought that he knew enough, but just when he thought that he had dug out everything about Si Huang, Si Huang would show more and let him understand that what he had discovered was just the tip of the iceberg.
