Of course, we cannot be sure who will qualify for the final because the group stage is not over yet. Some teams that stand out are worthy of being favorites, but regarding betting, I really believe that all teams are at risk of failing to win, so bettors must consider the risks wisely.
It is definitely not possible to be sure who will win the CL, if it was possible we'd all send the bookies parking, lol. The thing is, the strongest teams would be amongs the favorites to win the trophy and thus they'd get a lower odd, City are prolly the favorites, i would not best against them retaining their CL trophy, i can't see any team stopping them.
That being said, it is still a prediction and i could be completely wrong, that's why gamblers are always advised to gamble responsibly, so you don't gamble with what you cannot afford to lose.