The Scum Is Firm 

Kang Ce turned and looked at the corpse of the creator of the illusions. What Cheng Sheng meant by having a firm heart is being decisive in everything, not changing their choices so as to prevent them from being fickle-minded, which can be detrimental. However, being like this also has its downside. 

That is, when they commit a mistake, like what happened with Kang Ce before towards Xiao Le. Kang Ce was firm in his decision to split with Xiao Le, breaking Xiao Le's heart. Thus, Kang Ce entirely lost Xiao Le's heart and he can never take him back. Now, Xiao Le is with Shu Mu, and Kang Ce sees that Xiao Le is happy with Shu Mu. Shu Mu also loves Xiao Le, thus Kang Ce's heart becomes more resolved in letting go of Xiao Le despite the pain and sadness that he feels. He then chose to work as Li Nanzi's right-hand man and reform the Huli Sect for him to distract himself.