Board Thread:Theories and Speculation/@comment-25319479-20160816140121/@comment-4271790-20160816193922

I would think Sasuke told Sakura. I'd speculate that Sakura would be curious as to why her hubby went from wanting to kill Itachi to doing a complete 180 and becoming defensive of Itachi and wanting to destroy Konoha, then doing another 180 and deciding to ultimately protect Konoha thanks to Itachi's sacrifice.

As seen in chapter three of Gaiden, Sarada knows that Sasuke is the only full-blooded Uchiha left thanks to Sakura. So I'm sure Sarada would have been curious as to why the Uchiha was so scarce. Either Sakura explained to her the reasons why (assuming Sasuke told his wifey that) or Sakura maybe told her "We'll tell you when you're older".

Or perhaps, she could have been told about what happened with the Uchiha clan and Itachi from Naruto. Which would make that three people whom Sarada communicates with that also all possibly know of Itachi's life (I say "possibly" because Sakura is 50/50 like mentioned above).

I wouldn't be surprised if Sasuke himself told her, because I wouldn't think Sasuke would like his own daughter to believe his beloved brother and her uncle was evil. If she knew, I would think that it would be kept a family secret in order preserve Itachi's wishes to maintain honor with the Uchiha name.