(idiomatic) To be absolutely certain, to have no doubts.
I'd be surprised if those two are still dating come Christmas, but I'm not betting the farm on a breakup just yet.
2016 October 24,Owen Gibson,“Is the unthinkable happening – are people finally switching the football off?”, inThe Guardian, London:
Since Rupert Murdoch famously bet the farm on Premier League football to rescue Sky TV in 1991, it has been the catnip that has underpinned subscriber loyalty and, even in a far more complicated media landscape, is seen as so vital as to be worth almost any price.