RevealTo reveal is to make something visible, to expose something, to perform an action, or say something that causes something previously unknown to be known.
EX: Before the proctor would reveal the test questions, she had to make sure that each of the students had the proper identification in hand.
EX: Jill knew that an article about her family's past might reveal the long-hidden truth about the source of her large inheritance, and she worried about it night and day.
The expression to show one’s true colors means to reveal a person’s real motivations or to show their actual character.
EX: Heidi thought that Amy was one of her closest friends, but Amy showed her true colors when Heidi was given a promotion and the friendship was damaged.
EX: Thankfully, the jealous and domineering young man showed his true colors before the wedding ceremony could take place.
Leak OutTo leak out is to be revealed bit by bit, in small parts over time. If something leaks out, just a few people are told and the number of people in the know grows over time. In a physical sense, liquid or air can leak out of a container bit by bit.
EX: Rather than make a big deal about it, she preferred to let the news of her political appointment leak out over the next few days.
EX: As the helium in the balloon began to leak out, its ability to stay afloat lessened until it lay on the floor, disappointing the little girl.
The expression let the cat out of the bag means to reveal information that was previously secret or to leak a secret.
EX: He had planned not to tell anyone else about his intention to scale the mountain while on vacation, but he let the cat out of the bag by ordering a harness over the phone in front of his roommate.
EX: If Julie hasn't mistakenly let the cat out of the bag by now, Tom should be very surprised by the dedication of his new office this evening.