Waterloo Bridge (1931) was Bette's third film. In her autobiography, The Lonely Life, Bette wrote, "Universal, now irrevocably convinced that they had been duped, made the best of a bad bargain and cast me in Robert Sherwood's Waterloo Bridge in which Mae Clarke played Myra opposite Douglas Montgomery's Roy. I was his gentle sister, Janet, who is kind to the hapless heroine. And that was that!" (Davis, 117).
She wore one hat. You can just make out a bow on the band on the right side of the hat.
Bette's performance was not mentioned in the reviews. You can watch the film below.
Davis, Bette. The Lonely Life: An Autobiography. G. P. Putnam's Sons, 1962.Ringgold, Gene. Bette Davis: Her Films and Career. Citadel Press, 1966.