1940s 0r 1950s Fim,American.about 2 Sisters in love with 1 Man Due to a mix up of names .the man choose the wrong sister ,the other one moved away and became a nun.there was a Thyphoon or flood which stopped anyone going to the Nunnery. After years the Nun rsolved the problem and found her lover .I think.it could be with Ann Blythe ,but I am not sure.

Green Dolphin Street (http://www.tcm.com/tcmdb/title/1121/Green-Dolphin-Street/)