stuck in my head

hello everybody
there is this Chinese isekai that is in my head but i don't remember the title its about this girl that has been reincarntated a couple of times and she is reincarnated again in the same time as her previous life but now she is a princess and sister of the guy that killed her in her previous life she knew that he was still innocent so she decided to teach him martial arts so that he could protect himself after a couple of years the guy falls in love with her but its not incest because she isn't actually the daughter of the emperor
if you know this manga or something that sounds like this please tell me