Were most of the characters skeptical?
The only person I think was skeptical was Naruto, and he has since found out that his reasons for being skeptical (holding onto 3 year old memories of Team 7) were wrong. But since the reader identifies with him, that colored the rest of the scene, regardless of the truth.
I think the rest were surprised that she would put a love confession to Naruto ahead of killing Sasuke (*cough*cough*

).
Skeptical, angry. They weren't exactly happy, for whatever reason. Most likely because they sensed she wasn't being honest. But, why else would kishi make them look that way? Because it was meant to be viewed as a tense moment.
QUOTE
I think she has dealt with her feelings for Sasuke. (That's my interpretation.)
In chapter 458, she started bawling her eyes out when she realized how much Naruto loved her.
Then she opened her eyes in shock, then hung her head in shame, we she thought that she was hurting him.
(So she has had her eyes opened about Naruto.)
In chapter 459 page 10, she tells Shikamaru: "... please... don't say anything more..."
I think that is the moment she finally dealt with what she felt (past tense) for Sasuke, on top of all the subtle changes in Part II that led up to that moment.
Unfortunately, that isn't enough to say that it is 100% true. While I do agree Sakura seems to show very deep love for Naruto, the story is about bonds. This includes non-romantic bonds that are even more strong than romantic ones. The most important love in the story is non-romantic love between Naruto and Sasuke. Given that Kishimoto is so fond of showing love minus the romance, it is possible to say Sakura's reactions aren't romantic in nature.
Not saying that I believe this, but that it is a possible outcome.
QUOTE
What would need to be shown to make you think that Sakura has dealt with her feelings for Sasuke?
(That sounds more combative than I want. This is an honest question.)
For us to be shown that she has overcome them. She hasn't been shown as such, but this is mostly because kishimoto wants to stretch out the pairings, I think. If she can speak to Naruto truthfully, without hiding something, without lying or seeming false, then of course I will accept her intentions towards Naruto. But face it, Naruto and Sakura are still very focused on Sasuke. Sasuke is the final obstacle for both of them, whether it be due to romance, or something else.
Don't misunderstand me, I have a lot of faith in NS. However, I am not about to ignore that I am not the author, and that the way I view these two characters and what paths I think they should travel may not be what Kishimoto intends to do.