
Yeah she saves Tia from death after all the evil thing she did to her in this second life. And no, she didn't regret what she did in her past life, she blame Tia for everything and think she was the victim and swore to take revenge on her in this second life, she only realize she was the villain not Tia at the end of the story.

SPOILER
I read a lot of spoiler and put all of them together. Ji Eun remember her past life too, she given two choice by the God Vita, Go back to Korea and forget everything or time traveled to the Kingdom again with her memories intake, she choose the later cause she think it was unfair, she was supposed to be a protagonist but Tia ruin her fairy tale even after her death. After Tia was executed, the kingdom began to fell apart since Tia was the one who do all the works but Ji Eun was the one who get credits, Ji Eun was really useless and Ruve began to compared her with Tia, how Tia now all his fav food within a weeks and Ji Eun didn't even know it even after years they are together and blah blah blah, even the people who used to praised her began to realize how useless she is and criticize her and for that reason she resent Tia and in the second life she swore to take revenge on her. She schemed together with Duke Zena. Only when Tia almost death for the second time in this timeline, Ji Eun realize her mistake and use her power to save Tia as redemption of all her wrongdoings.
JIEUN IS BACK!!!!!!!! So i saw this spoiler on ig of an episode where Jieun is found in the imperial lake and she remembers her past life like Tia...!! And she also saves Tia from death..