Sweetie Belle

Michelle Creber is the singing voice of  Sweetie Belle, “school-age unicorn filly and the younger sister of Rarity,” who makes her music ...

Sweetie Belle is best Cuddly Mini Composer by *SterlingPony on deviantART

Christmas Mash-up from Apple Bloom and Sweetie Belle
“Michelle Creber has a special Christmas message for the fans of My Little Pony: Friendship Is Magic.”

Yes, in a set on the Cutie Mark Crusaders, this third entry cleverly follows the below pattern, which is spaced by five days.

Source: My Little Pony

Squeaky Belle
“Every time Sweetie’s voice squeaks in ‘Sisterhooves Social,’ you have Sweetie-diabetes.”

Fifth episode of the second season, “Sisterhooves Social” explores
a conflict between Rarity and Sweetie Belle,
yet this image and meme were created independently of that episode.

SHUT UP SHUT UP SHUT UP by ~thedarklordkeisha on deviantART

Sweetie Belle Derelle | Know Your Meme
“Sweetie Belle Derelle is an exploitable reaction image featuring the character Sweetie Belle from My Little Pony: Friendship is Magic with her eyes ...”

Memetic Mutation is revealed with a list of examples,
“Fluttershy is a tree.
Scootaloo is a chicken.
 Sweetie Belle is a dictionary.
 Spike is Rainbow Dash.
 Rarity is a marshmallow.”

see more My Little Brony

World’s Worst- Miscellaneous
“This is the FAQ for the World’s Worst Fanfic series. A FAQ is a long document that no one reads, but is posted ad nauseum. Different FAQs are used for different purposes -- some aren’t even organized by questions, but are used as a soapbox for the author to rant endlessly in an almost completely …”

Another interpretation of Sweetie Belle is Sweetie Bot, a fan-made character of Friendship is Witchcraft, a series of videos overlaying scenes with new dialogue: CUTIE MARK ACQUISITION PROGRAM.

Sweetie Bot by ~zaiyaki on deviantART

Friendship is Witchcraft - “Neigh, Soul Sister” (5)
“When Rarity and Sweetie Belle get into a silly fight over whether or not they both have souls, it’s up to the Apple family to teach them ...”

This entire post had been building to that conclusion.