I can't get past the friend relationship with the the random npc girls. I've maxed out relationship and happiness. But for some reason whenever I try to kiss them on the date, it fails. Am I missing something???
To get past the Friend level you have to succeed in the date with a gift and a kiss.
Make sure you pick the right choices during the date as that also raises the chances.
Another suggestion is to use the Peppermint Candy item that's currently part of the Christmas event before going into the date as that will provide a bonus during dates.