The house of the liar
The liar will never openly confess him or herself as a liar. It would be a contradiction, will always deny it.
The liar will sometimes indeed believe in him or herself to be truthful, to be honest.
I have visited the house of the liar. I have been invited to stay in. Everything looks ordinary except for the walls and everything on them. They are made of thin paper which will fall once you close the door fiercely.