liars and nonliars

My sister inlaw has ink on her foot which reads "truth" or something stupid to that effect. Not sure how J is her sister, seeing their personalities are so different. I could say the same about my sibling, but he thinks tattoos are stupid, so perhaps his annoying elements are less permanent. Nothing against tattoos or people who have tattoos, but nothing about ink strikes me as being appealing. I suppose I can see the usefulness to indicate ownership like in times of slavery or for inventory reasons like during Nazi Germany, but nowadays it only makes sense to me for prostitutes to have tattoos, for in moments of undress they may need signage stating "insert here" or "do not smack," for ignorant patrons unfamiliar with coitus or that rough stuff costs extra.
Of course, I jest, for strippers need ink too! Naked women generally look a lot a like in dark, smoke machined rooms, and ink helps take one's eye away from various imperfections such as warts or botched operation scars. Not that I'm a patron of the arts, but rather remembering a time or two humoring a friend by tagging along. I'm too cheap for such pastimes but I observed various decorations upon performers which gave me pause. Sorry, but flames down the thighs makes me think of Johnny Cash's Ring of Fire which makes me think of burning venereal diseases.
Is there an antonym for liar that comes quickly to the mind?
Probably since anything can be contrued as a lie, for everything is subject to change.