It's not that Zhao Ying has any information unknown to Bo Jingshen, it's just the attitude cultivated from her experience over the years.
Facing different people, one should have different levels of vigilance.
For someone like Jing Ce, Zhao Ying would never feel assured. Even if she heard Jing Ce was dead, unless she saw him being pushed into a furnace and burned, she couldn't be fully certain that such a dangerous person no longer posed a threat.
So, what's more, if he was merely paralyzed and had lost his senses?
Zhao Ying's words alerted Bo Jingshen. Being in the upper circles of Beijing for so many years like Zhao Ying, it's true what they say—the old ginger is indeed spicier.
Bo Jingshen already had misgivings about Jing Ce, and with Zhao Ying's pointed reminder, he became even more vigilant.
"You are right, I will keep this in mind," Bo Jingshen replied very earnestly, "but this time it truly isn't because of Jing Ce. Xiaolu wants to help my sister."
