you can bet your bottom dollar
US /ju kæn bɛt jʊər ˈbɑtəm ˈdɑlər/
UK /ju kæn bɛt jʊər ˈbɑtəm ˈdɑlər/

1.
pode apostar, ter certeza absoluta
to be absolutely certain about something; to be sure that something will happen
:
•
You can bet your bottom dollar that he'll be late.
Pode apostar que ele vai se atrasar.
•
If she says she'll do it, you can bet your bottom dollar it'll get done.
Se ela disser que vai fazer, pode apostar que será feito.