Anyone's game noun
A game in which all sides have potential to win
The final match between team A and team B on Sunday would be anyone's game.
The expression is used at the beginning of a competition to say that you hope the most fastest, strongest, or most skilled succeed person
wins.
I will win no matter what happens.
To win only by a smaill amount; to win narrowly
Win something easily, or with less or no effort
If someone has a cast iron stomach, they have a strong stomach that can digest unusual food and even bad food without being ill.
Jimmy must have a cast-iron stomach, when he drank milk with lime juice and felt perfectly fine afterward.