He feels regret for rejecting her. It really is for her "own good," he reminds himself. Today, she actually had been easier to influence than he had anticipated. While she spoke about the absurd idea of assaulting her, he unconsciously thought of his hidden desire to kiss her, to see what her pureness tasted like. Even in this life, Sam still has typical male desires, even though he not kissed a girl since becoming an angel of darkness. It's strictly against Lucifer's rules, for Sam anyway. Sexual intimacy, even kissing, can cause emotions within a soldier he or she may not be able to control. It is common practice to be in this role for four centuries or more before being trained to be intimate humans. This is especially important in Sam's case since he has never encountered intimacy—beyond a kiss—even when he had actually been alive and of free will. It's easy to understand now why that rule is enforced. He is completely in awe of this stubborn girl. It's irrational.
