lol they dont need to come out and say it, its obvious all on its own. also not only that but this way the people who aren't into yaoi can still think of them as friends, and people who like yaoi can think of them as a couple. then you have people like me who cant really decide at all. but its safe to say its pretty canon, just type in Kurogane and Fai Clover, that scene makes it so obvious ^_^
actually i really disliked yaoi until i found this couple! i still don't really like yaoi but i will make an exception for these two lol. im still on the fence about it, but i also kinda go all fangirly when i see any amv or read any fanfic that pairs them as a couple lol.