@Celye lol, sorry for tagging you at this point, I suppose u already know but I'm still writing it, lol. Namjoo is the ML of the story, the guy who was in the accident and the one who forced on Juda, the FL, to have a relationship with him.
The reason why his dyslexia is important, it's because;
1) Their fake relationship is based on the fact that Juda would help him to hide that aspect of him, so that's why Juda ended up reading Danoh's BFF letter and other documents related to Namjoo and
2) Namjoo probably was focused in hiding his secret so her step-mother wouldn't take advantage of him because as it seems, she was the one who killed his biological mom in the past (but this is just my assumption, lol). Also, since he's probably fighting as his father's heir, it wouldn't be something good for him to have his secret revealed, how can someone who's supposed to be a powerful businessman have that "fault"?
Lmao, that's what my experience in manwhas and kdramas told me.