The Sins of Rachel Cade (1961)

In 1939, earnest missionary nurse Rachel Cade travels to the Belgian Congo but she no sooner arrives than Dr. Bikel, who runs the local hospital where she is to work, dies of heart failure. She also soon learns that the hospital has been a failure and has yet to treat a single patient. Slowly, Rachel gains the trust of the villagers, not only providing medical care, but preaching the gospel. The local government official, middle-aged Colonel Henri Derode, doesn't quite hit it off with Rachel at first, but soon begins to develop deep affections for her. The sexually repressed Rachel however has fallen madly in love with the dashing Captain Paul Winton, a American serving in the R.A.F., who is shot down and is also a medical doctor. Her moralizing comes back to haunt her when she learns after his departure that she is pregnant.