(one's)/the best bet
The action or idea that is most likely to be successful. At this hour, taking the highway is your best bet if you want to get there on time. This method of testing is the best bet for getting an uncontaminated result.
your best bet
the most favourable option available in particular circumstances.the/your best bet
(informal) the best thing for you to do in a particular situation: Your best bet is to leave the car here and get a bus into town.