Ji Changsheng actually didn't expect that the Mage Sanzang would agree so readily because this isn't the normal behaviour of parents.
However, Ji Changsheng quickly convinced himself: Cundi was never normal to begin with.
So the fact that Cundi agreed so readily seemed rather reasonable.
Sensing Ji Changsheng's surprise, Mage Sanzang directly asked, "Did you not expect me to take a gamble with Ling'er's life?"
It was indeed a gamble.
Because this matter was risky.
The value of Tathagata was very high, and getting higher.
The value of the "Corpse Skin Changing Scripture" was not as high, especially when facing strong opponents like Tathagata.
If Ling'er couldn't use the "Corpse Skin Changing Scripture" to replace Tathagata, she would end up being devoured by Tathagata instead.
This was also the reason many Saints, aside from the Heaven Connecting Sect Hierarch, did not think highly of the "Corpse Skin Changing Scripture" technique.