There were many reasons why Harry Potter approved of his best friend, Hermione Granger, dating George Weasley, but there was a sole one.
It wasn't because the two had fixed each other after the war.
It wasn't because George was Ron's brother.
The sole reason had only been shared with Ginny. It was because when Harry looked at the lively couple, he saw his parents. He saw fire and ice merging into something perfect.
The green eyed wizard remembered the things Sirius told him about his mum and dad. He could recall the stories about the hundreds of things that separated the two, and how neither put much thought into the differences. And when he looked at his best friend's relationship, he couldn't help but point them out.
After all, George was the trouble maker, Hermione was the goody good.
George had left Hogwarts, Hermione loved learning.
George was a bit of hyperbole himself; Hermione was calm.
But they weren't that different at all.
They both were extremely intelligent.
The two were equally stubborn.
They could sit for hours in each other's company, just reading.
When Lupin was still alive, he would take Harry to sit with him in front of the fire place in Grimwauld, and tell him about the fights his parents would have, and how those only happened because they both cared. It amazed the Boy-Who-Lived how much the two relationships compared. Hermione and George argued about a lot to be frank. They were both very, very, passionate people.
They were always having competitions to see who was best.
They would have arguments over how things should have played out in books
They would fight when one went too far
When the other forgot something important
When the other was ignorant of somebody else's feelings.
or what color to paint the walls when George moved in with Hermione, something that surprised everyone in the least. Everyone had thought they'd move into the apartment above the joke shop, where Fred had used to live. However, through all of this, they always made up, just like Lily and James had.
Watching the couple waltz across the ballroom floor of the Ministry's Wizarding War Anniversary Ball, Harry could see that the biggest things the two couples had in common were the way they looked at each other, and the way they looked when they danced. Every time their eyes met, when talking, when they were across the room from each other, or when fighting, it was like the other was all that mattered. And when they danced, Merlin, when they danced they were one person, just like his parents had danced.
In all honesty, George Fabian Weasley was the only man Harry would ever let take Hermione's hand in marriage. So when the whole room watched George go down on one knee, and the crowds started whispering as he pulled out a small box, carrying a delicate ring. Harry wasn't in the least surprised when Hermione Soon-To-Be-Weasley covered her mouth, and leapt on the tall Ginger. The two newly engaged people in front of him were after all, just like the best couple in the world had been.