April Idiom: Die Katze aus dem Sack lassen/ die Katze im Sack kaufen
Our April idiom is here:
'Die Katze aus dem Sack lassen'
The same idiom exists in English as well: 'To let the cat out of the bag' which basically means to reveal a secret, to give news, to show your true intentions.
Ich dachte, er sei zufällig hier, aber dann ließ er die Katze aus dem Sack und sagte mir, dass er extra gekommen sei, um mich wiederzusehen.)
(I thought he was here by chance but then he let the cat out of the bag and told me that he was here for the sole purpose of seeing me again)
This idiom is closely related to the idiom 'Die Katze im Sack kaufen' which means to buy the cat in the bag. The purchase was somehow hidden, not completely or honestly revealed. You are not really sure what you bought!
Leider kannst du das Haus nicht inspizieren lassen. Du musst die Katze im Sack kaufen, wenn du das Haus haben willst.
(Unfortunately, you can not have the house inspected. You must buy the cat in the bag if you want to own the house.)
Both idioms are said to have originated in the middle ages when merchants where not necessarily honest. They probably told buyers that there was a pig in the bag but it turned out to be a mere cat which was revealed when the buyer 'let the cat of the bag' so to speak.
The idiom is possibly also related to punishment on a ship. A certain form of whip was also called a 'cat'. If the captain of a ship "let the cat out of the bag" it probably did not mean good things for the sailors. After the cat was let out, the number of lashes was probably revealed.