He sounds more like he’s trying to convince himself rather than Lily. It’s hard but Lily can’t find it in herself to be mad at him. War is hard. It has made them all do things they regret. She won’t hold it against him. So she reaches out and pulls Remus into a hug. She whispers into his ear, smooth and sweet, "I forgive you." This is all it takes for Remus to break down in her arms. He’s silently sobbing, but Lily can feel the shakes trembling through his body. "Thank you."