bet one’s bottom dollar

“bet one’s bottom dollar”
you can bet your life: you can bet your bottom dollar
to be quite certain about something; used to say that you are completely certain that something is true or will happen
در خصوص چیزی کاملا مطمئن بودن
Example 1: You can bet your bottom dollar that he’ll be the next president.
Example 2: I bet my bottom dollar you can’t swim across the pool.