(someone's) best gamble

Translations
лучшая ставка (кого-то)
Investing in real estate was John's best gamble.
Инвестиции в недвижимость были лучшей ставкой Джона.
Definitions
A person's most promising or highest-stakes attempt at achieving something, often involving risk or uncertainty; the action or decision that someone believes has the greatest chance of success despite potential risks.