Hmmm... I feel like he really underestimated Kat in this chapter. she wasn't swayed by his practiced seduction because she could see it meant nothing, rather she was always reacted to his sincere emotions, so I feel like he should have known that even if he revealed the truth - your sister hired me, but I ended up really falling in love and terminated that relationship, she might have been shocked but she wouldn't have hated him.