Yellow Canary is a war film starring Anna Neagle as a socialite who is sent to Canada as a Nazi sympathiser. On the boat over she meets an Englishman and a Polish Captain.
Once there she is slowly to find out the Polish family are more Nazis ... and, yes you guessed it, the English guy is an English special agent sent to help her uncover this major plot.

And, the final scene shows her coming back home, a hero - complete with husband ... and all the Nazis in prison!
No You Tube as too obscure!