false-hearted

While he was in this state of love-lorn blindness the false-hearted knight Sir Mordred rode up with purpose to joust.

Magnus, it is impossible to deny that the male sex—lords and all—are most dreadfully deceitful and false-hearted.

What do you mean by leaving a man in this state, three weeks and more, you false-hearted wagabond?'

So all pitied the poor Vicar, despised his uppish, false-hearted wife, and most hated the young squire.