What you tell me about in the nights. That is not love. That is only passion and lust. When you love you wish to do things for. You wish to sacrifice for. You wish to serve. . . . You will. I know you will. Then you will be happy. . . . You cannot know about it unless you have it.

The priest talks to Frederic about love at the beginning of the story. At this point, Frederic has never been in love, as he freely admits, although he spends a lot of time with women. The priest refers to Frederic’s visits to the local bawdy house when he says “what you tell me about in the nights.” Frederic insists, however, that he feels happy, but the priest disagrees. He believes Frederic must love—truly love—in order to be truly happy. The priest gives a succinct definition of love that presages Frederic’s experience with Catherine as described in the story to come.

She went out. God knows I had not wanted to fall in love with her. I had not wanted to fall in love with any one. But God knows I had and I lay on the bed in the room of the hospital in Milan and all sorts of things went through my head but I felt wonderful[.]

Frederic reflects on his feelings for Catherine after they reunite at a hospital. They had been carrying on a romance at the front, but both saw their flirtation merely as a game. Upon seeing Catherine in the hospital, however, Frederic fell in love with her instantly. Later, Catherine risks her career and reputation to perform a sexual act not described in the book. Frederic’s sudden feeling of love instantly returns, his lust is satisfied, and Frederic and Catherine become inseparable as a couple from that moment on. Although the fact is never directly stated, Frederic’s recent near-death experience may have enhanced his willingness to experience true love.

Often a man wishes to be alone and a girl wishes to be alone too and if they love each other they are jealous of that in each other, but I can truly say we never felt that. We could feel alone when we were together, alone against the others. It has only happened to me like that once.

Frederic remembers his life with Catherine in the months they lived in Switzerland while she was pregnant. Their connection felt so strong that neither of them experienced loneliness when they were together, a rare experience according to Frederic. He attributes this contentment in large part to Catherine’s courage, meaning her confidence in herself, him, and their future. As Frederic remembers their relationship after Catherine’s death, he fatalistically attributes her death to the cruelty of a world that “has to kill” the brave in order to break them. She died as punishment to them both for being so happy.