Many asked him, why her? Why does he love her?
And he would answer, "It's her." Simple as that.
Of course, many people would push him.
"Seriously though, why do you love her?"
At this point he would smile and shake his head, knowing it was pointless. Although he knew exactly where they were coming from.
Many people, including his closest friends, believed she hated him.
When they told him this, again he would smile and shake his head.
"Nah, she doesn't."
That was one thing he never doubted. She did, in fact, not hate him.
If she did, why, when paired on an essay or seated as partners in class, did they talk as if they were the only two in the world. Why would she visit him in the hospital wing every time he was injured and keep him company for as long as she was permitted to? Why did they study together in the library every Sunday at the same time, going out of their way to meet there? Why did they spend time together at all if she, in fact, hated him?
It was the smiles she would give him whenever they managed to figure something out. The way the corners of her lips would tug upwards when she caught them in the midst of a pulling a prank. It was how one night on the astronomy tower, where she told him about her sister and he told her about how he worried for his parents' lives daily, both of them listening intently.
He knew chemistry like that isn't easy to fabricate.
Granted, they fought too much for his liking, mainly when he jinxed a fellow student, or when he overstepped a boundary between them. But he knew that standing up for people, placing herself in front of them, willing to sacrifice herself for other, was something that came naturally to her. And he loved this about her.
He may disliked her choice in company, but he still, somewhat, respected that it was her choice. He just didn't want to see her get hurt.
The day he saw him hurt her, it made his blood boil past its point. He saw it in her face and heard it in her tone, how hurt and disappointed she was. When she accused him of being just the same, he was hurt as well. Surely she knows him better than that?
Later he would see that it was the hurt and disappointment talking, especially since he all but forced her to see what had happened to her friend, her best friend. He wrote her a letter, just one, confessing how sorry he was for causing the scene that day. Embarrassing her like that in front of their whole year. She hadn't responded, he didn't receive one letter saying she had gotten his. However, when they went back he was surprised to see her seek him out and begin to apologize profusely for her words. She always knew when she had gone too far. They both did.
When they asked if she was pretty he would shake his head.
'She is beautiful in ways, you wouldn't understand.'
So when he was asked, why her? Why do you, James Potter, love Lily Evans?
"Simple." He would say.
Because she was Lily Evans.