Is my perfect fruit only perfect to me? [duplicate]

Perfect trees will only grow from perfect fruit in the town that they are native. If you give someone a bunch of perfect fruit from your town and they don't have that fruit natively, planting them will yield regular trees.

To get anything else to yield a perfect tree, you need to use Fertilizer on a sapling, but this hasn't been tested with non-native fruit anywhere I've seen.

In short, if the perfect fruit is a fruit native to the town, planting it will always grow a perfect tree. The game does not (and cannot) differentiate between a bunch of fruit. Otherwise you couldn't stack them. Anything that is unique to you (such as a signature sheet) isn't something you can drop, anyway.

On this page, which was also posted on the answer you've quoted, it is also stated that perfect trees will grow for native fruits, regardless of their origin.

In your case, if you were to share one of your perfect (native) pears with a friend that has native pears and he'd plant it, he'll get a perfect tree.
Vice versa seems to be true as well, which means that a perfect native pear that your friend has grown in his city can be planted in your city with native pears to get a perfect pear tree.