Source??
Her twitter, apparently. Another user here said so - I didn't personally see the post myself, however.
BD never said it.
BD did say something similar in her video tho. She wanted NK to suffer more, only that her readers didn't want that and so she decided to tone it down a bit. As for the particular tweet the other user spoke about, it could be possible that she did say it.
Apparently Byeonduck stated that Na-Kyum is going to suffer a lot more. The poor sweetheart. We'll have to brace ourselves, guys. Get our tissues ready. This is gonna hurt.