the betting (line) is (that)

the betting (line) is (that)

It is pretty likely that (something will happen or something is the case). That new intern is a nightmare. The betting line is that she's fired before the end of the month. I hear we're supposed to get over two feet of snow—the betting is school will be cancelled tomorrow.
See also: bet
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

the betting is that

it is likely that. informal
See also: bet, that
Farlex Partner Idioms Dictionary © Farlex 2017
See also: