The Stupid Faerie and the Arguably Stupider Half-Breed

There are many precise and persnickety rules of the Fey. Between them, it is rude to refuse a gift, but even ruder to say 'thank you'. They may even consider hosting their mortal enemy, and find that their only wrongdoing worth fighting over be that they did not bring an offering for the host. But there is one rule that no Faerie, Seelie or Unseelie, changeling child nor solitary Fey, may break: they cannot lie. Mortals brought to Faerieland through bargains and tricks refrain due to respect, but the Fair Folk of the forest refrain for an entirely different reason. They cannot lie. Magic warps their tongue, dries it out as if it were sandpaper, and leaves the sour taste of rotten fruit in their mouth. However, do not pity them, as they can still deceive and trick just as well, if not better, than those whose tongue lies freely.
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Or, it's really, really hard to keep your feelings a secret when you cannot lie. The half-breed manages to do it, however, and the silly faerie (Taehyung) is none the wiser.

BTS x The Cruel Prince by Holly Black!