
You can't really call it "change" when new life Ruve hasn't done anything shitty to Tia. At this point, it's a different person imo. ╮( ̄▽ ̄)╭
It's a matter of cause and effect. The author hasn't laid out everything yet about Ruve and all his actions.
The letter was indeed rude, but I can't really say it was all that HATEFUL, considering the letter was from a man whom he knows is ROMANTICALLY interested in HIS FIANCE (that he deniably has a crush on cuz he's a pubescent teen lol)-- of course he'll be intrigued.

we only know the mind of Tia in This story not Jieun or Rude. yes he was a jerk ass whatever you because i agree with you for the first Timeline.
But now he try to change to think by himself to understand to resolve with the every hit he find so we have have give him a chance not judge him because he didn't know what he do first and we don't know how he view Tia and in the firs timeline. that not excuse anything he do that will only explain
Ok but if he ends up with the prince it's going to be really fucking disappointing. I don't care if he's changed. If Tia didn't had a second shot at life I bet he would have forgotten about her and lived happily without thinking about her after her death. And also, if he hadn't read that letter ( which is rude btw bc just bc that letter was lying around doesn't mean he can read it. It's private and intimate, considering that ge is a fckin crown prince he shouldn't have read that letter bc its not his) i bet he'd still that clueless ass who'd likely make the same fcking mistake all over again