He didn't know how or when it happened. Harry just knew he had never meant for it to happen. He hadn't even planned on surviving the war. Even as he broke things off with Ginny at Dumbledore's funeral. He had figured at the time that if he did survive the war and won, that he and Ginny would get back together.
Not once had the possibility of falling for one of his best friends ever crossed his mind. But months on the run changed that. All he knew was that he, Harry James Potter, had accidentally fallen in love with one Hermione Jean Granger. It was something about seeing his bushy-haired female best friend all frazzled and ready to fight at a second's notice all while doing her best to ensure they all managed to eat something edible everyday that made him look at her in a different light.
Of course things were complicated by the fact that said bushy-haired friend seemed to have feelings for their mutual red-haired best friend, Ron. Feelings that had ran at least through all of sixth year as far as Harry knew for sure. Though it might've been for longer and he just wasn't aware of it.
So Harry played the good friend and kept his crush to himself. Deciding to let Ron have a chance with Hermione instead, especially since things seemed to head that way. And go that way they did….at least until some time after they'd managed to get Slytherin's locket away from Umbridge.
The three of them had been taking turns wearing the locket as a precaution; the idea behind it being that it would be less likely for the horcrux to influence one of them deeply the way the diary had so heavily influenced Ginny back in their second of them had ever expected the arrangement to still backfire in the horcrux's favor. Not even Hermione had seen it coming with her typical penchant for staying at least one step ahead of things. But this time, things blew up horrifically. Before they knew it, it was Harry and Hermione on one side of Hermione's shield charm and Ron on the other.
With a huff, Harry turned as Ron as stormed out of the tent only to see the heartbreak in Hermione's eyes as her eyes followed the red-head. Seeing that look in her eyes almost had Harry running out to jinx Ron for causing her pain yet again. Only thing stopping him was the bit of logic in his head, funnily enough in Hermione's voice, reminding him that Ron had already left the protective enchantments around the tent and disapparated to who knows where.
An inner part of Harry kept urging him to go and 'take his chance' with Hermione now that Ron was gone. Harry again kept to himself, for once in his life overruling his known savior complex, to give her time to get over it. It didn't mean it wasn't heartbreaking to hear her sobbing at night for the next few nights.
But eventually, her sobbing had ended. But her movements still matched her heartbreak. The light in her eyes was gone and every time Harry looked at her, he wished he could punch Ron for finally breaking her. Harry busied himself instead by flipping through the stations on the radio until he finally stopped as the beginning of a slow song played. Gathering his Gryffindor courage, he cleared his throat and walked over to her, holding his hand out to her.
"May I have this dance, Miss Granger?" He asked with a soft smile on his face.
Hermione looked at him in surprise and confusion, her mouth opened as she prepared to potentially question his sanity or just refuse him. But she closed it and thought better of it as she returned his smile with a small one of her own.
"Yes you may, Mister Potter." She replied as she slid her hand into his.
Harry closed his hand around hers and pulled her to a more open spot of the tent. He gently pulled her close, while still maintaining a respectable distance between them. As his other hand settled on the small of her back while he gently led them in a small waltz, his heart broke again at how thin she had gotten from the lack of proper sustenance. And he felt guilty and directly responsible for her health. After all, she was out here losing out on food because of him. He took a breath to calm himself only to find that in his brief moment of musings, she had closed the gap between them, her head resting on his shoulder. If he hadn't already known he'd fallen hard for Hermione, he definitely knew now. It felt right, holding her close to him, just the two of them as if the world outside didn't exist for this brief moment. Before he even could realize he was doing it, he softly kissed her cheek.
"I'm sorry." He murmured.
"For what?" She answered, a bit in shock from the kiss to her cheek.
"For putting you through so much. For dragging you through so much with me." He answered. "But that's all I'm sorry for."
She pulled back slightly to look him in the eyes in confusion. "What do you mean?"
He gently cupped her chin with a finger as he looked back into his eyes. "I'm not sorry for doing this…" He closed his eyes and gently pressed his lips against hers.
Hermione's eyes widened briefly before her eyes fluttered closed as she let herself enjoy the tender kiss. Her hand slowly cupping his cheek in return.
Harry deepened the kiss for a moment before finally breaking it and looking her in the eyes once more. "I'll never be sorry for doing that."
Hermione studied his face for a moment, her gaze lingering on his emerald green eyes the longest. She took in the genuine love in his eyes and knew then that she could never expect him or ask him to be sorry for that kiss. Her heart jumped as it slowly dawned on her that she would never want him to be sorry for it. She pressed her lips to his in a soft but brief kiss only to pull away just as briefly and stare back at him with the biggest and most genuine smile he had seen on her face since before Ron had left.
"Good. I don't want you to be. For I'm not sorry for letting you."
She never had planned it. She didn't know how or when it had happened. All Hermione Jean Granger knew was that she had accidentally fallen for one Harry James Potter.