What is the origin of the idiom "best bet" and when to use it?

The idiom "best bet" is believed to have originated in the late 19th century, with the first recorded use of the phrase found in the novel "The Light that Failed" from 1891. The expression likely evolved from the concept of betting on a horse race, where selecting the best horse to bet on would be the most advantageous choice. Over time, the phrase has come to be used more broadly to refer to the most reliable or favorable course of action in various contexts.