Well, you must be right... You always are.
5 seconds sound clip from the The Remains of the Day movie soundboard.
You can hear this line at 01:26:52 in the Blu-ray version of the movie.
Quote context
[...]
- You know what I'm doing? I'm placing my thoughts elsewhere while you chatter away.
- Then why is that guilty smile still on your face?
- Oh, it's not a guilty smile. Simply amused by the sheer nonsense you sometimes talk.
- You can hardly bear to look at her. That's why you didn't want to take her on. She was too pretty.
- Well, you must be right... You always are.
- Lizzie, aren't you supposed to be turning down the beds? You'd better get on with it, hadn't you?
- Have you told her yet? You'd better get on with it then, hadn't you?
- What can I say? She'd never understand about us.
- She's old. I mean, she must be at least 30.
[...]