The most incredulous of the wtf's, what the sincere fuck is used asking for clearification of something so fucking terrible it is hard to believe and one using wtsf is often looking to deny its happening or existence in the first place.
Bitch 1: The exam date has been pushed up 'cause of crysler's surgery
Bitch 2: What the sincere fuck??!!!
A phenomenon in where one song on an album feels out of place due to it not matching any other song on the album, comparable to the track Sincerely Me from the Dear Evan Hansen movie, which is an odd Black Comedy song on an otherwise mostly sincere and heartfelt soundtrack.
Tim: ever notice how I'm Gonna Win by Rob Cantor is weirdly different to all the other songs on his Not a Trampoline album?
Jon: Tim what the fuck are you on about
Tim: It's a total Sincerely Me Paradox
Jon: bother someone else
The act of using a phrase or word in a sincere or unironic manner, that originally was only used or meant in an unironic manner.
"What up, Fam"
"Bro, did you just say 'Fam' unironically? You used to make fun of people who say that."
"Oh shit... I guess I did."
"That is some Post-Ironic Sincerity"