Harry could tell that Dumbledore was disappointed when he arrived at their next meeting without the memory. Not that he cared. They watched Tom charm a woman who wore Slytherin's locket and then requests a teaching position at Hogwarts. Dumbledore explained his denial with trite about not trusting Tom Riddle, even at a young age, and not being willing to risk his students" lives. Considering that the same man had given the post to frauds like Lockard and lunatics like Mad-Eye Moody, Harry thought that a rather weak excuse.