So her older foster sister, our main girl was a orphan, committed suicide because another actress slept with boyfriend and I think (don’t quote me on this) the sister was pregnant. To get revenge on the other actress our FL became an actress to crush her. Then the girl she’s trying to get revenge on is interested in our male lead and that why our FL dates him but she starts to get actual feelings for him and feels bad. I don’t know the ending for sure but I will post if I find out, this is all I know so far.
I'm not fluent but i can read korean & understand little bit of it. Bfr the ending when ML propose to MC in award show. The bitch try to frame MC in a show, purposely looking pitiful saying that the person she loves is snatched away by rookie actress. So netizen obviously know who is this 'rookie actress' since both MC & ML already announced their relationship. As the thing she usually do, the bitch want to make our MC's reputation fall. But she is so stupid, she forget our ML. After ML saw the article, he called the jurnalist & her true face got exposed (she slapped employee of salon, the thing abt she made other actress suicide, also abt she got gift thousand won by man). That's the beginning of her fall. Then bcs of stress after that scandal she got addicted to drug. That's her ending. I'm so satisfied She got exposed in the end.