pls helpp

i have been reading one romantic fantasy manhwa and arrived till 51 ch. BUT i forgot its name. it was about girl who in her "past life" reads one novel and she fell for a villain in that novel. and she started having nightmares about him like about things that happened to him in novel. she wanted to help or like hug him in those dreams but couldnt. and then during sleeping, she went in novel and became a twin sister of female lead. but that character wasnt originally in novel. she had "soulmate mark" on her chest ever since she woke up in new world. and she and that villain really fell in love. but the problem is her mark. but that mark is suspicious hmm thats where i left off. about time where her sister and her soulmate got marks and wanted to get married or something.... ahhhh im really forgetfull