Animosity07

She must have peaked at highschool then as we know ended up mediocre and now has this complex because there's no one to confront her about it

SR's mother is all the red flags in a mother like damn, she's all gung-ho about marrying SR off now she's against dating because it's SH, a successful architect that has his own company all because of her ego which is by the way the most inflated thing in this series as apart from raising her children (which is a big deal but it's also her responsibility) she achieved nothing or contributed to the family to match that big ego

Or maybe the guy actually doesn't know she saw him cheat so he has the balls to woo her again

BSR was raised by a woman who feels she lives a mediocre life and a father who swims in inferiority complex that probably has a lot to do with how she didn't tell anyone that she was diagnosed.

She was set up to be the golden child filled with expectations so she didn't plan to tell those she's closest with as her priority was not making her parents worry at the time, was hiding it the right thing to do, absolutely not but it make sense with her character and backstory.

Also I feel a lot of people are getting so caught up with the twist and is clouding up their mind, it's not as if she was just diagnosed and is dying, the shock factor of it all is not to be a scare and moreso as a setup to break the walls between the leads because she didn't tell she was gravely sick before