The phrase "put a false front" implies an act of deception, pretension, or insincerity. Therefore, the antonyms for this phrase would be honesty, authenticity, and transparency. Being honest and transparent means presenting oneself genuinely and truthfully without any hidden agenda or ulterior motive. It is the act of being straightforward, open, and sincere in one's actions and intentions. On the other hand, authenticity is about being true to oneself, without pretending to be someone else. It is the quality of being genuine and original, without any duplicity or hypocrisy. These antonyms represent the opposite of putting up a false front by demonstrating honesty and authenticity in one's behavior and communication.