I have read statements/watched interviews by several North Korean escapees, and nearly all of them mentioned how they bought into the propaganda at least a little. But it wasn't in the way that you would expect; it's mostly fear-based. As we all know, North Korea is built upon the cult of personality of the Kim family; the dictator is said to be an all-knowing god. And because surveillance can only go so far, children are told that Dear Leader can actually read their thoughts. This idea is so continually enforced that former North Koreans have reported being too scared to even
think about wanting to leave. It's only when they "get away" with thinking such thoughts that they realize that Dear Leader isn't as omniscient as they say he is.
Also, I've read that many North Koreans buy into the propaganda that the United States, Europe, South Korea, and basically the entire rest of the world want to attack and harm them, and that the Kims are the only thing that's keeping them safe. Many of them don't realize that the opposite is true; the rest of the world is extremely concerned about their living conditions and wants to help them.
Oh, and here's a really interesting short documentary about a girl named Yeonmi Park, who escaped North Korea and went on to become a South Korean television personality who tries to educate people on what's going on.