Very sweet, especially considering the victory quote between them in the Main Arc though I don't really think its romantic at all. --- I'm a gamer dang it, not a pc gamer or a console gamer, just a gamer.
I really do love that victory quote, though. I feel like the interactions with Richard in F arc really solidify their friendship. It shows that after all that they went through in the main arc, they came out of it stronger friends than they were.
And as someone else said, it's a follow up on a victory quote in the main arc, where Richard politely brushes Sophie away when she see he is hurt.
The quote is just plain adorable by itself, though. --- If I'm being ignorant, please enlighten me.