Hondo (1953)

Hondo Lane, a despatch rider for the cavalry, encounters Angie Lowe, a woman living alone with her young son in the midst of hostile Apache territory. She presumes she is safe because the Apaches, under their chief Vittorio, have always left them alone. Later Lane has a run-in with Angie's reprobate husband and is forced to kill him, not knowing who he is. Vittorio captures Lane and to save his life, Angie tells the Apache chief that Lane is her husband, unaware that Lane has killed her real husband. In order to protect her from a forced marriage with one of the Apache, Lane reluctantly goes along with the lie, though he knows the truth must eventually come out, to Vittorio and to Angie, both.