Sorry, but before you ask, no, Betty McLeish isn’t secretly Mama Shaw from the Fast and Furious franchise. Betty’s real name is Lilli, and she is also a German who immigrated to England after the war. The daughter of a factory owner, we learn in the big flashback towards the end of The Good Liar that she and her family were disgraced by an unknown party. That person is none other than Hans Taub, who as a young man, was an English tutor to Lilli, and an object of her affection.
Article source: https://www.cinemablend.com/news/2484956/the-good-liar-ending-what-happened-and-who-really-conned-who