I don't think that there is any sport that can give you guaranteed success each and every time but somehow I feel that betting on cricket is much easier for me to make some money as you can easily predict what will be the end result depending on the teams and if you have good knowledge then it will become more easier for you to win in it.
The question is very easy, we know that not all sports are guaranteed to give us profit. And as the question is asking, it is only wanting to know what sport is easy to wager, all of them are easy but the hardest part is to win.