- Do you know who I am?
- Only that you are to be known as Mrs. White.
- Yes. It said so in the letter. But why?

8 seconds sound clip from the Clue (1985) movie soundboard.

You can hear this line at 00:05:48.502 in the Blu-ray version of the movie.

Quote context

[...]

- May I take your coat? It is Colonel Mustard, isn't it?

- No, that's not my name. My name's...

- Forgive me, sir. Tonight, you may well feel obliged to my employer for the use of an alias.

- And who are you, sir?

- I'm Wadsworth, sir. The butler.

- Yvette, could you attend to the colonel and give him anything he requires. Within reason, that is.

- Do come in, madam. You are expected.

- Do you know who I am?

- Only that you are to be known as Mrs. White.

- Yes. It said so in the letter. But why?

- May I introduce you? Mrs. White, this is Yvette, the maid. I see you know each other.

- Hello.

- Hello.

- Want a lift?

- Yes, please.

- Thanks. I'm late for a dinner date.

- Me, too. Where are you going?

[...]