I don't think Naruto is fully one hundred knowing Sakura is in love with him. If she is indeed in love with him., while the things are apparent, we are still not 100% sure, but there is a good chance she is.
Let me also keep this real by saying that Sai didn't say "She is in love with you." He knows that she is doing this all for him now, but he also said that she loves Sasuke. To Naruto, this is a bit confusing. I would be confused as well. Everything that has been said to Naruto either is telling him the opposite of what he believes or telling him the REAL truth. He is confused right beyond all belief and like Kakashi said, he needs to find the real answers for himself.
I only said that HE thinks she is lying. Not that she really is. Since the manga is in the point of view of Naruto, I think he still believes she is in love with Sasuke. Everything is not black and white in the manga so we're going to have keep watching to see what is going to be the final solution. There is is a good chance that everything we believe WILL happen, but Kishimoto has pulled twists before so I am leaving my mind open for now.
Sai said she has "given up on Sasuke and confessed her love for you" or in the other translation "moved on from Sasuke and chosen you" "her only thoughts were of you and I think you know that" That sounds like saying Sakura is in love with Naruto to me. (and as I said that was the only time in the chapter that Naruto pictured Sakura in his mind as she is now, a serious minded young woman) And no Naruto didn't think Sakura was consciously lying, he never said that. He believed she was deluding herself about Sasuke, not lying about her feelings for Naruto, especially not after she got so angry. Note Naruto's lack of anger and his arm waving in 470 when Sakura laid into him about the truth of her feelings for him. Naruto's confused trying to take in that she loves him but still has feelings for who Sasuke was, and because of that she's going to kill Sasuke before he loses his last trace of humanity.
Naruto said in the last chapter not "she was lying" but "I knew she was leaving something out" there's big difference.
Now Gaara has reinforced Sakura's choice about Sasuke, and tried to do so in the kindest way. He doesn't know about Sakura's choice but he gently urges Naruto to make the same one, attempting to give his message with kind hand on Naruto shoulder- which Naruto in anger throws off. Naruto's still trying to gasp at his illusion of Sasuke even with the illusion of Team 7 shattering due to Sakura's decision.
Bringing the shooting the rabid dog analogy back again- Sakura is the person who sees the pet is rabid and the only way is for someone that cares for it to shoot it quickly and with as little pain as possible. Naruto is the person in denial about the pet, not believing it's rabid and believing whatever is wrong can be cured if he can just reach the pet.
Dream you dream alone is only a dream, but dream we dream together is reality- Yoko Ono 1971
When you go to war, both sides lose totally- Yoko Ono
Remember, our hearts are one. Even when we are at war with each other, our hearts are always beating in unison- Yoko Ono 2009