I firmly believe that Fleur Delacour and Viktor Krum remained friends after the triwizard tournament and that one night while they were celebrating Fleur and Bills engagement a very drunk Fleur bet a not as drunk Viktor that she could catch a snitch before him and so they competed and he won and Fluer lost her end of the bet saying that she would name her first born after him
and that is why their kid is named Victoire and the only reason it isn’t spelled with a k is to annoy Viktor