- But tell me why is Count Dracula keeping you prisoner?
- I cannot tell you that.
- But if I am to help you, I must know.

8 seconds sound clip from the Horror of Dracula (1958) movie soundboard.

You can hear this line at 00:13:46.545 in the DVD version of the movie.

Quote context

[...]

(DOOR LOCKING)

- At last I have met Count Dracula.

- He accepts me as a man who has agreed to work among his books, as I intended.

- It only remains for me now to await the daylight hours when, with God's help, I will forever end this man's reign of terror.

- Mr Harker, you will help me?

- If it's at all possible.

- But tell me why is Count Dracula keeping you prisoner?

- I cannot tell you that.

- But if I am to help you, I must know.

- I'm sorry, it's not possible.

- You make it very difficult for me.

- After all, I am a guest here. If I'm to help you I must have a reason.

- A reason. You ask for a reason! Is it not reason enough that he keeps me locked up in this house, holds me against my will?

[...]