After reading what Osananajimi means I assume that the childhood friend from the won't win. But to be fair, that isn't unexpected. Mostly these rules apply to romance manga/anime:
Rule 1: Childhoodfriend never wins. At least in like 95% of the cases.
Rule 2: If you have a love-triangle situation, in most cases the first girl that was introduced wins.
Rule 3: The further apart two characters are in the beginning (they hate each other, she is a "tsundere"-character), the likelyhood of her winning a love-triangle increases.