Grace Livingston Hill 
More Than Conqueror 

When Charlie Montgomery, a handsome soldier, declares his love for Blythe Bonniwell, she realizes she should be offended. But she isn’t—in fact, she’s honored! Blythe returns Charlie’s love, and promises to remain faithful to him while he is at war.
Though thrilled at Blythe’s response, Charlie knows all too well that the special mission he has been assigned to means that he is facing almost-certain death. He can offer Blythe little hope for his return or for their future happiness.
Yet, in the midst of fear and peril, Charlie and Blythe find a source of strength and peace that will keep them united forever.