Mistress Samantha wanted to test whether this guy was suitable for what she wanted him to do for her. So she used her fisting fetish to test him and he passed the test even though she fisted him painfully in the ass. He had a high threshold for pain and she was impressed with him. She offered him the position immediately when she was done testing him and she knew he was up to the task.
Mistress Samantha noticed rebellious behavior in her new slave and she did not like it. She felt that he would be a problem later on and she did not want to take any chances. So she used her fist to fuck him in the ass and she made him feel pain he had only read about and that made him change and he never angered her as he knew what she could do to him.