Most naive of the Mane 6?

[Soobel 488]

About Pinkies wisdom or intelligence: She feel failed, if one pony of the big crowd not laugh for her pranks. It means that her humor most be have very high quality for ponies and creating good humor is very hard and difficult task. Stupid or naive pony cant do this.

About awkward acting sometimes: Pinkie feel first, if things start going hopelessly wrong and she start pranking for fun, when other still trying save the situation. I remember moment from "Bird on the hoof" when Pinkie sits on the table and front Celestia and eats cupcaces. That sight between Pinkie and princess!   And fun starts, first Celestia pranks with that teacup, then Flutershy goes left with sic phoenix and...

[~ Dr. Ocsid ~ 690]

I don´t think Pinkie is very naive - except on a social level. There, she isn´t very good at understanding other ponies.

Although she is far more open than her sister, there are some similarities: Both find it hard to understand other ponies feelings.

Pinkie masks this by always trying to be happy, funny, and make others laugh: Joy is the one feeling she understands the best, and even here she is still learning. 

[KiwiPony 125]

I agree with the post above mine ^ (my phone isn't letting me quote it today :c) because Pinkie is naive on a social level however she often knows what's going on, in her own way, she's very excitable however underneath it all she knows what's going on.

As for Fluttershy being the most naive? I can't really understand that either, she's extremely focused on animals and so sometimes she can appear naive to situations however its because she has her priorities, and I'm not sure how being shy makes her naive...

[Dulset Tarn 441]

Twilight. Though to be fair, that's what happens when you've spent your whole life as a student and then you get thrust into a position of supreme power.

[Xeltor23 704]

Pinkie is for me the most naive. She tries to make everyone happy, and she always succeed. However, she doesn't seem to understand when people just can't or don't want her to make them smile, she almost force them to do so, thinking that they are shy. She has good intentions, but she's childish.

[Sombra369 3]

I agree RD and Pinks are the the most child like in presentation of the main ponies, RD is mostly immature and ignorant while PInkie Pie is Innocent and simplistic. Naivety comes in the form of RD's lack of interest and empathy in things not related to her and her inability to accept things that aren't related to her some form of action and thrill. Pinkie is naive because she doesn't understand the order of self control or tact because she wants/needs to experience joy, fun, and happiness while she remains free of anything opposite of those, she also wants everyone to enjoy life because she does in her own pov.

Well, what defines naiveté? Twilight, far and away the most intelligent of the Six, didn't know how to interact with others. While Pinkie, not the most classically schooled of them, often picks up on subtle things that others would miss.

 

So rather than say which is the most naive, I'll simply go through each and what areas they are lacking and may very well have improved on.

 

Twilight: General social naiveté.

 

Rarity: Lack of foresight.

 

Pinkie: Emotional immaturity.

 

Rainbow Dash: Lack of communication skills

 

Applejack: Unorthodox and "outside the box" naiveté.

 

Fluttershy: . . . Actually I can't think of one for her. She's not really lacking in knowledge of awareness of anything in particular, including her own shortcomings. So I guess while none of them could be described to be totally naive, it's actually Fluttershy who's the least so by my account. Who'd a thunk it? 

Mind if I fix that. RD is the one who doesn't connect on a emotional way to her friends and is too direct and insensitive to many strangers.

 

Pinkie is the autistic esqe one who has trouble with characters because she's a child trapped in a grown womans body.