Wiktionary
vb. (context idiomatic English) Said to emphasize that something is known for sure.
Wikipedia
Take It to the Bank is the second EP by American country music artist Chris Janson. It was released on February 25, 2014 via Columbia Nashville. The album includes material that Janson recorded while signed to the former BNA Records.
Usage examples of "take it to the bank".
So I have to have somebody they don't know take it to the bank with my letter of instructions.
But you can take it to the bank that Russell Bent thought the two Lansky kids were enough like him and his sister to merit dying.
But, anyway, he'd take it to the bank, and open an account for the International Foto, Motion Picture, and Television Corporation of America.
Pay 'em in camel shit, and tell 'em they can take it to the bank for money.
If I say something along those lines is so, you can take it to the bank.