From Genius:

"Guns N Roses guitarist Slash – who wrote most of the music for this song – wanted the repeat of the chorus to change to:

Where the girls are fat
And they’ve got big titties

Lead singer Axl Rose didn’t go for it. Instead it follows with nice sights most Americans long to find. Particularly for being better than usual (after all, the grass is always greener on the other side).

Note the alliteration: grass, green and girls."

Thanks for the fun fact! I didn’t know this.

We always used to sing … “Where the girls are green and the grass is pretty”