When it comes to expressing one's true nature, the phrase "show true colors" is commonly used. However, there are several synonyms that can be used instead of this phrase, providing a fresher perspective. One of them is "unmask oneself," which means to reveal one's true character or intentions. Another synonym is "reveal one's true nature," which is fairly self-explanatory, and "unveil one's pretense" which means to expose one's false pretenses. Additionally, "expose one's true self" is also commonly used in place of "show true colors." Using these synonyms instead of the common phrase can make your writing more vibrant and engaging.