Kang Sun is a depressed woman suffering from very low self-esteem because of how she got together with Ga On's dad this time around. in her mind, she will forever be the poor mistress who bedded her way to the top. She tells Ga On that she alone is her lifeline and that she needs to do what it takes to rise to the top of the company ladder in order to save her mother. She doesn't care if Ga On herself takes the top seat or if she finds herself a man to put into that seat. She wants it so that no one will ever look down on her or her daughter again. (Source: Dee at MyDramaList)