Hi:
Eoe: The other Bette Davis twin movie was
A Stolen Life, made in 1946. The twins both fall in love with Glenn Ford. When the good twin realizes that Ford prefers the vivacious twin,(who, of course, is selfish and greedy) the good twin steps aside and resumes her painting career. After Ford marries the bad twin, the twins take a ride on a boat which capsizes. The bad twin (who, by the way, has been cheating on Ford) drowns, and the good twin pretends she is his wife. Are you confused?

Glenn Ford and I were, too.
By the time Ford realizes the good twin isn't the one he married, he has already fallen in love with her, and, of course, he finds out his wife was cheating on him. So, it all ends happily ever after.