A memoir by a Korean-American author about teaching English to adolescent boys at a private university in Pyongyang was certain to anger the North Korean government.

But the author, Suki Kim, may have provoked even more anger among the university’s Christian educators. They have denounced Ms. Kim for breaking a promise not to write anything about her experiences and said her memoir contains inaccuracies, notably her portrayal of them as missionaries, which could cause them trouble with the North Korean authorities.

The private university, the Pyongyang University of Science and Technology, was approved in 2001 by the North Korean authorities, despite their distrust of outsiders. Fenced and heavily guarded, the university opened eight years later. It was there that Ms. Kim secretly took notes as she taught English in 2011 to 50 teenage boys and young men drawn from North Korea’s most privileged families.

It is unclear whether the school will suffer any repercussions because of the book, “Without You, There Is No Us” (Crown Publishers), named for a lyric in an ode to the ruling Kim family, often sung by the students in their regimented routines.