Double standards, of course. It's just blatant hypocrisy, nothing more. If Karin gets close to Sasuke, she's a nasty whore, but if Sakura does it it's omg true love.
If Sasuke tries to kill Karin, it's YAYYY SK IS DEAD, if he tries to kill Sakura, THIS LUB IS SO TRAGIC *CRIES*!
Honestly Sakura was not any more "pure" than Karin even as a child
at the part where Naruto disguised as Sasuke runs away before kissing her, she thought he was going to fap at least in one of the translations I saw, and in the Forest of Death she wanted to watch Sauce pee
They'll say that that was just back when Sakura was a fangirl and she really loves him now, but doesn't Karin have similar development?? Except Karin had a reason for liking him from the start, lol
So it makes me lol when people say Sakura's love is more "pure", GO REREAD THE MANGA