And they lived happily ever after. The end.

I thought i did it well but i guess not since there was still some confusion over it and someone even asked me what plot twist i am talking about.

Near the end of the chapter the ghost basically realises that Giyoon is lying or pretending like he can't tell the difference so the ghost basically calls him out for it and the chapter ends with giyoon's shocked reaction with him realising that the ghost is on to him. 

Chap 39 which is upcoming will also go into slightly more detail on Giyoon's past promise and why he is pretending like he doesn't know or see ghosts.   Yes Giyoon was pretending all this time, this is not up for debate, he was pretending.