Actually "you've never really seen him" is a mistranslation, what he actually said was more like "he displayed power he's never shown before."
Anyway I disagree on some points. If she was the way you described her then she wouldn't be special to Naruto, but she is. She, along with Iruka and the rest of Team 7, was one of the first people to acknowledge him, and saved him from the hell of loneliness. She supported and recognised his strength long before the rest of the Konoha 11 did. Remember Naruto's fight against Kiba during the chuunin exam? She was literally the only person (besides Kakashi) who didn't doubt him, who believed in him. And she was able to recognise his strength right from the start, as when he was fighting Kakashi during the first bell test she remarked that he was "pretty good," and was amazed by him when he fought Zabuza and later on when he showed up on the bridge she excitedly screamed his name.
The reason she didn't recognise the depth of his feelings for her is because he kept them hidden because he didn't feel worthy, because he hadn't kept his promise ("How can I [confess my feelings]? I can't even keep my promises...") On the contrary, I think she knew him well enough that she knew how Naruto would react to the news that the K11 was planning on offing Sasuke (it was one of the things that contributed to his hyperventilating and fainting), and how he would react to her trying to get him to give up on Sasuke, which is why she never planned on telling him the truth in the first place.
I think Sakura and Kakashi and Iruka are Naruto's biggest supporters, clearly. Her support is strongly shown in scenes like when she was going to give up the chuunin exams just so Naruto's dream wouldn't be crushed, and during the CPR scene when she said she absolutely wouldn't let him die and thought of his dream and how it's "right in front of them."
But I disagree that Sasuke is one of his biggest supporters. At this point, he doesn't support him at all (he plans on killing him and stealing his dream), and even in part one, when Naruto was getting stronger and stronger, instead of being pleased or proud or something, he got jealous and vindictive. He acknowledged him early on, sure, but acknowledging is not the same as supporting. And, I think Sakura is one of the people who understands him the most -- some examples showing this are when she conveyed his feelings to the alliance, and when she knew that the reason. But of course she can't understand him in quite the same way as, say, Iruka and Sasuke do, because they had similar experiences as Naruto, so that's not her fault.
No no no, he never said that. The closest is when he said that he felt like portraying Sakura as an "honest girl, with a surprisingly stubborn impression" during the confession.
Really?Sorry I found it in google. 
I don't remember what he said but I'm sure he said confession was true.
