I am very happy, that this is getting a manga. But, the manga lacks the tension, that the novel had, since we get to know a lot about what kazuki was thinking. For example: The scene where he meets the main heroine's mother, he had a long monologue, which made the scene much more better.
If you want to read the novel, you probably have to put up the third volume - which is by far the worst volume, since the pacing feels different and we don't get to know wtf harold is thinking - since it gets way better after that, starting from the end of the volume.