[It's -- it's still bizarre, the notion of Itachi having guilt. The awareness of it is fresh, the loss of him a second time (a knowing time, the loss of the entirety of his brother and not just the image this one is so desperately trying to construct) still bleeding its disbelieving truth into Sasuke's mind. That Itachi felt guilt even now should likely be something he knows, but to know it directly like this is something completely different from extrapolating.

Telling Itachi the truth was unkind, but Sasuke doesn't particularly know how to be kind -- but he can try, inasmuch as Uchiha kindness passes for it. He pauses for the first time, thinking about his words in a way to which he is deeply unaccustomed, and finally:]

I thought I hated you for a long time. [And even through all of that hatred he'd known his own choice had made it so, that Itachi had been the fulcrum on which his life turned.] I was angry at you after that, even after I knew I had failed to understand you.

Your resolve never falters. [If this is a genjutsu -- the Hokages' or less likely Madara's -- that is no piece of information that they don't already know, that isn't already writ large on their history. And the emphasis is clear, because Sasuke knows full well how his own choices have been made.]