10%
ready for controversy? i can only put this at a ten because they had very little interaction in any of the cannon medias. they had a very awkward thing at the beginning of way to wonderland and some little thing in dragon games before the kiss. also i don't know if you noticed but apple is so set on her destiny that even if apple liked darling i think apple would be in a very deep well of denial and therefore crush any crush she had. i put it at a ten though because if they had written more interactions between them i could see it working.
random thought: does anyone else not really like darlings voice actor or is that just me? its just really high.