Well, the manga of 'Ao no Exorcist' has more detailed backstories for some characters that the anime doesn't fully cover. Also, the anime sometimes alters the order of events for better flow on the screen.
The main differences are in the pacing and some minor character developments. The anime might speed through certain plot points compared to the manga.
The best chapter pointer here is Chapter 23, "Became Trending for Being Scolded". It opens with Although Jiang Li exerted very little strength, Jiang Yan instantly felt... and closes on However, just as she buried herself in the study, pouring over mysticism....
If you want the clearest chapter reference, go to Chapter 20. Early on, Several people turned their heads upon hearing the sound and saw three...; later, the chapter leans on She was clad in a long black dress, and the dull color did not hide her....
Look to Chapter 48 for the clearest answer. It begins with He Yun felt guilty for initially ignoring Jiang Li on purpose, and with..., keeps building through That's why he gave her the Perfect Card right off the bat., and lands on Besides, everyone's phones will be replaced with special.
Chapter 887, "So the truth is you like me?", is the clearest early answer because the hidden truth stops feeling like mere subtext.
A practical answer is Chapter 45, because it turns the idea into a concrete scene. The chapter opens with Helplessly, Jiang Yan had no choice but to step on the accelerator., adds pressure through Not one of these three ladies is easy to deal with!], and ends on The guests have to go through so.
A practical answer is Chapter 40, because it turns the idea into a concrete scene. The chapter opens with [Jiang Li claims she copied this herself?, adds pressure through Suddenly, someone typed in the live stream chat— "Oh my god, everyone,..., and ends on The handsome guys on this show are so.
A practical answer is Chapter 76, because it turns the idea into a concrete scene. The chapter opens with Thinking of this, the aunt repeatedly praised, "Girl, hearing your words..., adds pressure through Leaving aside whether what she's made is good or not, just taking these..., and ends on Soon.
The best chapter pointer here is Chapter 72, "Jiang Li Resembles an Early Capitalist". It opens with Jiang Yan was still griping when suddenly a fair hand reached out beside... and closes on Think about it." Jiang Yan fell silent..
Chapter 894, "I Want to Attend the Same University as My Sister", is the clearest early answer because it turns Jiang Cheng's situation into a concrete plot event.
Chapter 49 is the strongest chapter-level answer because it starts from My phone!!!" Jiang Yan's roar echoed continuously through the mountains in... and follows through on Thinking this, Jiang Yan marched forward, pulled Jiang Li down from her....