to be left incomplete...
There are always those moments in time when you feel that someone you love deserves the world. Those moments when you want to give them something big but you can't and you're angry with yourself for that.
James Potter the second felt the same way. He felt the need, the urge, to give people what the deserve. And he would give it to them.
If someone deserved a kick in the pants, he'd give one. If he felt someone deserved a hug, he'd give one. If he felt someone deserved a kiss, he'd give them one.
So when Aleta turned up at Hogwarts, James knew she deserved somebody to love. She was going through life, trying to live it to the fullest, but she was falling. James knew she deserved someone there, someone to walk besides her, someone to catch her if she falls. And he knew he would be the one.