I did have a brief look through the sub but couldn’t find anything, sorry if this has been posted before.
I was reading through the comments on the latest chapter when I had a thought. The overall plot of the last few arcs has been the kozuka (spelling?) knives and their ability to steal another’s power. CSG and co are hunting the gang to collect all the fairy tale powers for vlad, who holds the fairy tale card. So the theme at this point in the story is pretty fairy tale heavy.
Many fairy tales involve a princess who has some sort of curse/ailment that is fixed by a prince/knight, commonly by way of true loves kiss. This happens in Cinderella, Snow White, sleeping beauty etc. (modern versions, ik, ik, the originals are a little darker).
So my theory is this. The princess (momo) has her curse (amnesia) lifted by her knight in shining armour (okarun), and we all know it will work because okarun is her true love. Now, whether this happens in 3 chapters or 3 arcs is a different matter, but I’m pretty sure that okarun laying a fat one on momo is what will bring her back.
Again, this might be a common theory and everyone and their mothers might have heard it but it was just an interesting thought I had :)