You (can) make book on that 

This expression can be used in reference to quickly explaining an idea, motive or action to make a very firm point. It's a way of saying that something is certain and will happen no matter what. The use of the word 'book' is synonyms with 'print.' Once something is printed (i.e. newspaper, novel), it is permanent.

"The Breakfast Club" (1985)
Vernon says, "Now, I may not have caught you in the act this time, but you can bet I will."
Allison laughs.
Vernon replies, "You can make book on that, missy!"

"Don't worry they will spend her money one day, you (can) make book on that."

You (can) make book on that by Ryder Williams January 9, 2009

You (can) make book on that 

This expression can be used in reference to quickly explaining an idea, motive or action to make a very firm point. It's a way of saying that something is certain and will happen no matter what. The use of the word 'book' is synonyms with 'print.' Once something is printed (i.e. newspaper, novel), it is permanent.

"The Breakfast Club" (1985)
Vernon says, "Now, I may not have caught you in the act this time, but you can bet I will."
Allison laughs.
Vernon replies, "You can make book on that, missy!"

"Don't worry they will spend her money one day, you (can) make book on that."
Source: Ryder Williams, New York

You (can) make book on that by Ryder Williams January 21, 2008