This is how you know you're in love with her, these tears. The tears come every time she's upset, every time there's the slightest hint that something might be wrong. When she tells you about the boys that she loves, and the ones that don't love her back, even the tiniest tremor in her voice can set you off. At first you assumed it was jealousy, envy of these people who could capture her heart so effortlessly when you are automatically confined to the category of friend, but then, as you hated them for hurting her, you realised it was so much simpler. You wanted her to be happy.
Ginny is all smiles whenever she is being watched, and wistful when she thinks she is not. You watch her more often than not. You see behind the smiles. You know logically that half the time she is probably considering an essay due for Snape or thinking about the next Quidditch match, but you worry all the same, desperately wanting to be able to do something, to make her smiles genuine.
The thought that she is not happy, even if it is temporary, is enough to reduce you to tears, tears that you hold back until you are alone, tears that in retrospect seem so silly and trivial – why are the tears never shed for your own sake, rather than hers? Has your own life been so diminished by this love that you no longer feel pain or anger or anything else, just echoes and amplifications of her emotions?
When she tells you about the girl she loves, and the girl who doesn't love her back, and it is not you, because it will never be you, then you sob, and you know that this time the tears are your own.