When you want to express that something is a sure bet or a guaranteed win, there are plenty of synonyms for the phrase "you can't go wrong." Some options include "foolproof," "fail-safe," "bulletproof," "guaranteed," "flawless," and "perfect." You might also consider saying that something is an "absolute certainty" or a "slam dunk." Additionally, you could declare that something is an "unbeatable choice" or an "infallible option." Whatever phrase you choose, the goal is to convey confidence and assurance that the decision being made is a surefire success.