Su Xinyi nodded and said to him, "The reason I'm asking you to go is because you've been serving by the Crown Prince's side for a while, so your presence won't draw much attention. Remember, your most important task is to protect the Crown Prince, and other than that, do not write back unless it's a significant matter."
If Wu Shun frequently reported the Crown Prince's whereabouts through letters, and this became known, she would definitely be accused of spying on the Crown Prince.
Even if she were the Empress, let alone the Crown Princess, she wouldn't be allowed to freely pry into the Emperor's whereabouts.
Wu Shun hesitated for a moment and asked, "Crown Princess, what would be considered a significant matter?"
Su Xinyi choked for a moment and looked at Wu Shun, "What do you think?"
Of course, it would be a matter of life and death. She couldn't casually mention it, as the expedition was imminent and it would be inauspicious.