You (can) bet your (sweet) life phrase
You can be absolutely certain that something is true or will occur.
You can bet your life that he is a liar.
You can bet your life that she will be the next chosen applicant.
You can bet your life that he won’t dare to express his love to her.
Meaning absolutely certain or without a doubt
Another way to say "absolutely", "definitely" or "for sure"
That's absolutely right.
Totally certain.
With absolute certainty; decisively
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.