Mistress Nica knew that for her to get access to the secrets that this guy held, she had to hypnotize him which she did with great efficiency. Since she is hot, it was easy for her to hypnotize him and then she directed him and she got all the juicy details she wanted from him as he was not in control of himself and he told her everything he knew.
Mistress Nica did not want this slave to lie to her. She could tell he had lied but she wanted to be sure. So she used brain fucking hypnosis to get the truth out of him without him even knowing what was going on. The mistress then went ahead and she punished him after she had confirmed that he had indeed lied to her. He never lied to her again after that punishment.