
HeadInTheClouds:
Not sure if this have been discussed.
When do you think Jing resized that FFB is XL?
Like XY, TSJ would have recognized that FFB's face was the same as XL's face from the first time he met FFB in chapter 16 and presumably wondered about it. XY confirmed that. She also thought that TSJ would have used the Tushan Clan's resources to look into FFB's background (similar to the check that XY asked CX to run for her after XL confirmed that he was FFB), but he presumably wouldn't have been able to find any info that CX wasn't able to find with his sources and spy network.
And then FFB went and lived with TSJ and FFYY... I imagine TSJ probably tried to keep tabs on FFB to try to figure out if FFB was XL or not during that time, but we (the readers) aren't told much about it so we don't know if TSJ would have picked up on any hints.
In chapter 18, TSJ spied on XY and "FFB" in the maze at little Zhu Rong's residence when XY was talking to "FFB" about him having nine faces and 81 forms and what the real FFB looked like, and it's possible that TSJ could have overheard some of that conversation. But it seemed to me like XL noticed when TSJ arrived and (unlike later circumstances... like chapter 37) he didn't want TSJ to hear their conversation, so he cut XY off and tricked her into throwing an ice dagger at TSJ to force TSJ to reveal himself.
After emerging from his 37-year coma in chapter 22, TSJ would have come to know that XL saved XY's life, confirming that there was still some kind of relationship between XL and XY after WXL became XY.
TSJ told XY in chapter 24 that he felt like FFB was XL when "FFB" scared XY into his arms after she told him that she wished she could have saved him from the death match arena, and XY avoided the topic by saying that she didn't want to talk about FFB or XL. Although TSJ could have been hiding the fact that he already knew that FFB was XL, I personally think that it wasn't a deception and TSJ only suspected that FFB was XL at this point and was not yet completely certain of his identity.
In chapter 26, TSJ overheard XY telling XL to cut it out when she reacted to him increasing her heart rate, and then encountered XY returning from the direction of ocean with "FFB" the next day. If he didn't know with certainty that FFB was XL at that point, I imagine his suspicions would have increased after that.
And in chapter 29 XY found out that Li Jie Chang knew that FFB was XL and assumed that meant that TSJ knew too. If TSJ didn't know before that night, it seems very likely that Li Jie Chang would have talked to TSJ about FFB/XL after finding out that TSJ was in love with XY and that XY was close with FFB/XL.
And then even if he wasn't 100% certain earlier, TSJ definitely knew with 100% certainty that FFB was XL by chapter 32, when he made a deal with XL and then "FFB" invoked XY's promise to prevent her from marrying Feng Long.
TSJ admitted / confirmed to XY that he knew that FFB was XL when she went to confront him in chapter 33.
My sense is that TSJ strongly suspected that FFB was XL for a very long time, but wasn't absolutely, 100% certain until Li Jie Chang confirmed it around chapter 29 and then XL further confirmed it in chapter 32.