ML is innocent, naive, child-like

Good Doctor- ML is autistic and basically has the mind of a child. Initially, I thought it would be really weird but it turned out to be cute AF. BTW, the show is also a medical drama and doesn't focus solely on romance.

Shopping King Louie-ML gets amnesia and becomes childish...more childish than he was before his amnesia.

Prince of Wolf-ML was raised by wolves and the FL brings him back into society. Honestly, I dropped it because the FL started acting dumb and creating unnecessary misunderstandings that only served to drag out the plot. You might still enjoy it though.

I Hear Your Voice - ML isn't really child-like, but FL is a noona character, who kinda looks after him.

 xinya:

I Hear Your Voice

+1 great drama

also noona romances and child like innocent ML - caring FL (though I hear your voice is best fit): 

Find Yourself 

Encounter 

Something in the Rain 

When I Was the Most Beautiful (but this drama is way more complex and deep and GREAT then just noona romance)

Angry Mom same actor ))) not main theme and not romance, more one sided love but really good story line, I watched drama because of it, though drama has serious and interesting subjects 

not noona but fits:

Reply 1988 - childhood friends, this guy is definition of child like innocent naive kind and positive (as actor Park bo gum himself)

I'm Not a Robot fits good

Backstreet Rookie fits quite good, though ML is older 8-10 years as I remember, but Ji chung wook is so childish and cute here )))

Dream High ML is good fit, though wouldn't say FL is caring type, ML is more caring