As my late father use to say: “she’ll lie even if the truth sounds better.”
“Pathological lying, also known as mythomania and pseudologia fantastica, is the chronic behavior of compulsive or habitual lying. Unlike telling the occasional white lie to avoid hurting someone’s feelings or getting in trouble, a pathological liar seems to lie for no apparent reason”
https://www.healthline.com/health/pathological-liar