- I realize, of course, that there aren't any mailboxes that you can drop a letter in out there in the wild. You better read it.
- But that doesn't keep me from worrying about you.

16 seconds sound clip from the The Treasure of the Sierra Madre movie soundboard.

You can hear this line at 01:14:46.470 in the Blu-ray version of the movie.

Quote context

[...]

- Hmm. Few hundred pesos.

- Name was James Cody. Dallas, Texas.

- There's a letter from Dallas, too. Must be his home.

- Reckon she's his girl.

- Not bad.

- Dear Jim, your letter just arrived. It was such a relief to get word after so many months of...

- Silence.

- Silence.

- I realize, of course, that there aren't any mailboxes that you can drop a letter in out there in the wild. You better read it.

- But that doesn't keep me from worrying about you.

- Little Jimmy is fine, but he misses his daddy almost as much as I do. He keeps asking, when's daddy coming home?

- You say if you do not make a real find this time, you'll never go again.

- I cannot begin to tell you how my heart rejoices at those words if you really mean them.

- Now I feel free to tell you, I've never thought any material treasure, no matter how great, is worth the pain of these long separations.

[...]