Britney Spears Writing Social Media Posts from the Heart, No Help from Her Team

Britney Spears conspiracy theorists are back at it -- suggesting she didn't write one of her recent, emotional IG posts ... but we've learned she definitely did, and meant every word.

Sources with direct knowledge tell us ... Internet claims that Britney's social media manager, Cassie Petrey, is the one who crafted her Thursday IG post -- the one about fairy tales and Britney's life not being one -- are complete nonsense.

If ya missed it ... some of Brit's fans speculated the post was intended as damage control following her explosive court hearing Wednesday, and pointed to her mentioning her family in a somewhat positive light as proof.

Our sources say this is totally false -- just like the previous rumors that Cassie writes her posts -- and insist Britney has always been responsible for all of the messaging on her social media and always will be.

We're told Britney's social media accounts don't do scheduled posts either, as some fans believe, and she posts whenever she feels like it. We're also told social media has been the one positive outlet for her where she doesn't feel controlled ... so fans should believe what she says there.

Our sources add that Britney's digital team is very proud of her for speaking up in court about her conservatorship, and they note she had no complaints about social media during her testimony.