Where did you get the idea that Karin hates Sasuke's guts now? There's absolutely nothing in the manga that says that. In fact just the opposite. In the manga canon she says- paraphrasing a bit here to explain the emotional context of the scene better- Cries out in anguish- "Don't do this Sasuke! Then plaintively reasoning with herself- "Maybe I should give up on him now."
That's the last we get of her true feelings about Sasuke. Her reasonable self is saying this guy is not right in the head, but her heart still cares.
Kishimoto has made it pretty obvious Sasuke will have some kind of redemption and has a decent chance of living after his redemption. My gut says if Kishimoto does go down the lives after the redemption plotline path the most likely as a chastened man- a wanderer looking to truly redeem himself and discover who he can become free from living a life being yanked around by the chains he has lived under from his legacy and by his own doing. (Naruto has successfully made most of that journey, Sasuke's hasn't begun and will be harder because he mostly willingly took the path he knew was wrong)
I've read these chapters... It hasn't been confirmed, as in... IT IS NOT CANON YET!!! The confession does not show her actual intention, she could've been bluffing Naruto into coming back to Konoha with her, so therefore the "confession" has not yet been proven to be canonical evidence of Sakura having romantic interests in Naruto because Sakura's motive for "confessing" was not yet shown.
There is a difference between Canon and Confirmation btw, Canon supports and Confirmation makes it the real deal...
Furthermore, maybe I was being a little melodramatic on my part after saying "Karin hates his guts!" but she certainly doesn't want to get involved with someone she views as crazy...
She's not THAT masochistic ¬_¬