She had a great disdain for
Dagmar Lassander. When Lassander was cast for a major role alongside her in
Hatchet for the Honeymoon (1970), she made sure that her role was expanded while Lassander's part was shortened. Also, she treated Lassander very derogatorily. Decades later, Lassander claimed that Betti was "very rude", but didn't share any details out of deep respect for the older actress.