You´ve put your finger on it
Lenka: Tell me Lukas, why can´t I keep a man for more than three months?
Lukas: You´re too demanding, too strict, you leave them at the slightest imperfection and overall you expect too much.
Lenka: That´s it! Lukas, you just put your finger on it! You really understand my situation.
Lukas: So does that mean you´re going to change?
Lenka: Of course not, I just wanted to hear what I´m doing right.
Dictionary:
You´ve put your finger on it- You´ve found the answer-You´ve found the truth
