Lately I was into Investigation/Romance/comedy dramas & cause of it I watched "Oh my Ghost", "The Girl Who Sees Scents" & "Master Sun" & I loved them, 

I was searching something similar. It has to have some investigation (Murder or anything else) and be Romantic & Funny, 

I would like it to be supernatural (Like in Oh my Ghost seeing Ghost, something like that) but It's fine if it doesn't have it.

So anything ?

Who Are You (2013)
I think you may like 'Arang and the Magistrate' as it has all the things you seem to be looking for. It is funny, magic, romantic and there is a murder mystery to be solved.

You're All Surrounded 
7th Grade Civil Servant
Call of the Country
I hear your voice
I remember you
Pinocchio
Thanks you all very much ! Some of them look really interesting ~ off to watch them xD ~