- Well, no doubt he lacked assurance.
- No doubt.

4 seconds sound clip from the Phantom of the Opera (1943) movie soundboard.

You can hear this line at 00:38:30.626 in the Blu-ray version of the movie.

Quote context

[...]

- Speaking purely as an inspector of the Sûreté, I'm afraid that even the obvious often needs confirmation.

- But as a man, Monsieur Daubert, you can understand that sitting there in the orchestra pit night after night and looking at Christine, Claudin probably fell in love with her.

- You admit that is possible, no?

- Christine, did Claudin ever seek more than a casual acquaintance with you?

- No, never.

- Can you imagine so diffident a lover, monsieur? Claudin was barely 50.

- Well, no doubt he lacked assurance.

- No doubt.

- This is yours, Christine.

- You're giving it to me?

- Yes.

- Well! Then I'll accept it as a gift from both of you.

- Well, I seem to have got the worse of this bargain.

- In the future, Monsieur Inspector, I detect, you model.

- In any case, monsieur, that was a bad clue.

- Not so bad as it seems. It enabled me to recover mademoiselle's statuette.

- Thank you, Raoul.

[...]