Hypnotizing slaves is what this mistress likes to do in her spare time. She loves how much power it gives her over her slaves and anyone else she is humiliating. She loves to tease as her primary way of humiliating them. She loves to make them enjoy her teasing and then she brainwashes them and gets them to do what she wants. It is always fun as she gets to have fun and to sometimes financially humiliate them.
Princess Kate could not believe what her slave had said about her behind her back. She did not like people who could not face her and tell her any issue they had with her and since it was her slave who did it, she did the same thing by humiliating and degrading him through hypnosis. She used it to gain total control over him and when he had, she made him do all the nasty things she wanted knowing he would not know she was involved.