While I would normally agree with you, this is the one case where the author has made me feels it's a believable conclusion. If we're talking abt the Cardinal, we can't use logic; he lives his whole life based on the fact *God has given him another chance at life.* To him, he has died once and has been brought back by God Himself-- and although this seems mostly metaphorical, to him it is very much literal; he's a very cunning, intelligent guy but his religiousness and absolute belief in God comes first and foremost in regards to his character. And, who knows? Maybe it WAS divine intervention. IDK where the author is taking this.
But besides that (the Cardinal's belief as to what happened to him), I think it's because Shuri is not *only* overly confident, but also mostly correct, and truly someone that changed completely from one day to the other. Everyone notes on how she was "trembling" one day, but taking complete control of her life the other. It really is more "out of the blue" than you'd think possible, too, given her age.
I understand where you are coming from but I still don’t believe that he would think that this is her second life. Like mb “god or someone helped her” or “she can see the future” or smth like that, but I doubt he’s thinking “this is her second life”. The Cardinal didn’t go back in time like she did. He was simply saved from drowning (mb by god or it could’ve totally been by a character who is involved in the story which would be a nice twist >:3 ). Anyways that’s why even tho he had “a second chance at life”, it is no where near the same as her “second chance at life” which is why I believe that he wouldn’t of thought of that possibility even with his deep faith. Does that make sense? ( ̄∇ ̄")
I just wanna say… HOW DOES ANYONE POSSIBLY THINK THAT THIS MUST BE THEIR SECOND LIFE AS AN OPTION? IM JUST SAYING! If this was any other person they’d simply think “oh they r overconfident cuz the r a fool” or that “their overconfidence will be there downfall” or find some other reason as to why they r so confident. NEVER IN A MILLION YEARS IS SOMEONE GONNA THINK “oh she’s so confident, almost as if it’s her second life.” =_= even if anyone was even to REMOTELY think that, they’d just brush it off as impossible, not actually think it’s a possibility. I DONT CARE HOW SMART OR DEVOTED TO GOD U R, THAT IS SIMPLY NOT CROSSING UR MIND. :/ ahem sorry, just had to get that off my chest cuz it was bothering. It might just be a plot device in order for the cardinal and the mc to have a chance to work tgthr instead of being enemies but I just feel like that was so out of place. But ofc, this is a fantasy afterall so I’ll just accept it now that I’ve finished my rant~
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