Board Thread:Show-Related Questions and Answers/@comment-24386552-20140301181911/@comment-29405550-20140311013710

The reason TLK doesn't work is because their memories are altered, they no longer love that person. It worked for Snow in 1x16 because his heart-warming speech made her fall for him again and she kissed him and it worked. TLK isn't the only way altered memories can be restored. Such as in 2x22 and 3x12 a magic potion restored their Belle, Sneezy, and Emma's memories.