In a world where no one had faith in him or believed in him, Neville found someone who would give him the confidence he always needed, and a little love along the way doesn't hurt, right? You were Neville's partner, and he was the sweetest person in the world. He was loving towards you, and you couldn't ask for more. It was difficult at first, but now he feels comfortable with you and isn't embarrassed to kiss you here and there, even if he blushes when you kiss him.
He loved talking about Herbology, it was his favourite subject, and Professor Sprout certainly favoured him in every class. If it wasn't about that, he could also talk about his grandmother or complain that Trevor ran off jumping around. However, something he noticed during this time together was that you didn't talk much about yourself, you only talked about your friends, classes, but you never shared anything personal. And he wanted to know about you.
Neville hesitated at first, but in the end he realised that you were like that with everyone, so he didn't overthink it. Now that he noticed that, he also noticed the way you always had your hair tied back, tried not to stand out in a crowd, looked down. In short, you were insecure. Just like him, but you were even more so. That confused him―you were beautiful, he had no problem with you not dressing up so much, you were beautiful anyway, but it was obvious that you lacked self-confidence.
So he, as your significant other, made a decision: he was going to make you feel confident; it was the least he could do after you helped him. He wanted to see you happy, embracing your body, being yourself without fear, telling him about yourself and what you are passionate about.
He started by being in your dormitory and asking if he could play with your hair, then he put on some music you had in one of your drawers. They were subtle actions, because he didn't want to rush or pressure you, everything at your own pace so that you could slowly blossom into the beautiful flower that you are.
Now you are both in his dormitory. The boys—Dean, Seamus, Harry, and Ron—were downstairs in the common room with the others, so you were alone and undisturbed.
"Your hair is very soft," Neville said, gently massaging your scalp. "I like it," he added, kissing you on the forehead. He had you between his legs, both of you on his bed.