Most likely....lying? I mean,usually,you can't trust when a liar says their lying,so then 당신 think that they are lying that they are lying. I hope that makes sense,somehow...
Liars don't lie about everything, just most things. If they're a good liar, there's no way to tell unless 당신 go digging for the truth, and even then 당신 might not really know. If they're truly a liar, then despite any suspicion 당신 may have, 당신 will never be sure. The liar may not even know that it's a lie themselves.
if a liar is lying when they say they are lying are they telling the truth? they are probaly lying when they say they are lying so if a liar lies when they say they are lying they are lying and telling the truth!
It is a 질문 that cannot be awsered with one awser so KohakuSMA kind of made it impossible