Trust
Disclaimer: I am not J. K Rowling, I do not own the rights, nor am I likely to, to her series of books.
Trusting people is a strange business. You sit in the rocking chair and gaze at Harry. Your precious baby boy, one of the two things you'd give up anything for. Your lives depend on trust. Without it, both of you, and James, oh James, why aren't you home yet? would be alone and lost and almost certainly dead.
Marlene is dead. You still can't get your head around that. Your best friend in the world is dead. She put her faith in the wrong person, she thought Rabastan had changed. She'd never been in love before and she fell for him. She fell hard, the way you did for James, but you had a soft landing and she, she had the light snuffed out of those gorgeous black eyes, the smile wiped from the face that so closely resembled Sirius', her cousin.
Your trust is in Peter now, though so few people know that. He would never betray you, he swore to James and his best friend, one of the marauders, they could never betray eachother. Oh Merlin please let my husband come home tonight, please, please, please. Where is he? Why did you let him go? Lily you stupid, stupid girl, you shouldn't have let him go, what will you do if he doesn't come home, can't come home? He's your husband, you love him, oh please come home James!
Back to trust. You have to trust James, you have to trust Dumbledore, Remus, Sirius, Peter, Alice, Frank. If you're truthful, the hardest person to trust is yourself. How can you know you won't go wrong, let them hurt Harry, hurt James, hurt anyone. You can't do that, don't let that happen. Please don't let them get hurt, not ever. You'd die for them now, if it would make them safe. Trusting yourself is something you can't do so you trust doubly in other people and hope it makes up for it. It doesn't, not really.
*Knock, knock"
James!
You run to the door and ask the question. "What did Tuney call us?" When he answers correctly you slowly open the door and flings yourself in his arms. James, James, James, James. You're safe now, I won't let you get hurt, I promise.