When she awakens here in her own house and it's dark, you should be able to convince her that it was all a dream.

6 seconds sound clip from the Back to the Future Part II movie soundboard.

You can hear this line at 00:39:19.115 in the Blu-ray version of the movie.

Quote context

[...]

- Marty, Einie, brace yourselves for temporal displacement.

(DELOREAN ENGINE HUMMING)

- Did we make it? Are we back?

- We're back.

- Let's put her in the swing. Then I'll take you home, and you can come back in your truck and wake her.

- When she awakens here in her own house and it's dark, you should be able to convince her that it was all a dream.

- Wait a minute. We're just gonna leave her here on the porch?

- The disorientation will help convince her that it was all a dream.

- How long do you think she's gonna be out?

- I'm not quite sure. She received quite a shock. Could be for a few minutes. Most probably, a couple of hours.

- You better bring smelling salts back with you.

[...]