Qin Fangtian once said that the Tao Rhyme cannot be sought after, only encountered, and it imposes strict requirements on perception and cultivation. Ordinary cultivators don't qualify to study it, and it is necessary to start with the baptism of four Thunder Kalpas.
To Lu Bei's knowledge, the only cultivator who undoubtedly possesses Tao Rhyme is Zhong Yuxiao, a remnant of Qingqian, whose single sword shocked the world with its dominating gaze.
Bai Jin has an excellent comprehension capability. Even from a mere painting, she could acquire some enlightenment. If she claimed to have understood the Tao Rhyme, Lu Bei won't doubt it.
The key issue is one's cultivation level. At the early, no, the mid-term integration period, one is very far from a cultivator who has passed the trial of four Kalpas. Isn't it premature to comprehend the Tao Rhyme now?
More accurately speaking, Lu Bei suspected that she was faking it.
To make sure he wasn't fooled, he decided to verify it personally.