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Movies like Princess Charming (1934)

Revolution breaks out in a small European kingdom, and a young princess is forced to flee for her life. She heads for the neighboring country, which just happens to be ruled by the king she is betrothed to. Unfortunately, the new revolutionary government won't let citizens leave, which she actually doesn't mind all that much because she's not particularly jazzed about marrying the elderly king. He sends a young naval officer to bring her across the border, but in order to do so they are forced into a marriage of convenience. Complications ensue.