Do you think Ash was pretending during DP062's main scene?
Ehhh...you can't separate the writers's will with the anime story.Pokemon anime is mostly used as marketing tool and like the DIRECTOR(the former) said: "girls are replaced for candy eye" so yeah,writers play a big part on that.Although...
As for me,I try to view Satoshi's density from an " inside the anime " spectrum.
It is one thing I prefer to block the writers fro interruptions,because Satoshi's character is already defined,writers can't change that.
As I said,I keep writers in mind in most cases,like the case of "never gonna be canon because of the writers" thing.They probably don't want too screamy things,Kasumi was screamy enough for most saying that it is undeniable er love for Satoshi,even I agree with that.
But after AG and the candy eye,marketing being implemented hugely...even Kasumi cameos seem to be less screamy,maybe that's why she was somewhat cold with Satoshi.It is like they are trying to remake her feelings.
But I'll end the off-topicness here.
The thing is that Pearl wasn't that affect by those aspects of the anime,Pearl actually getting the better of it.
The innocent,not to screamy relationship turned out to be awesome,and thinking for a second,they are VERY close but they aren't in love.Which could mean that they didn't realize about it yet.
Marketing actually protected Pearl....Pizza Commercial,Movie posters,SatoHika everywhere in Japan....
And the part of the writers themselves,we have Tomioka.He is the main scripter and he definitely wrote many Pearlshippiness.
So yeah,we actually are blessed by marketing stuff
The only thing that was bad,was Hikari leaving the series for nothing at all,just for BW games and blah blah blah.
But returning to the question,he was pretending.
Since my vision on his character is inside the anime,Satoshi just plays the fool...he actually would know when a girl is flirting with him and everything.Writers made him dumb about that,but EP09 is the proof that he always knew about girls.Hikari is just as dense as he is...while they can't get everything,they ger the important part 70% of the time.
Satoshi being the ONLY to notice Hikari's sadness during DP61 is already enough proof for that above,and for Satoshi just playing the fool in DP62 too.He just turned the situation much lighter,just like their friendship is.Light,innocent and pure
So that said,yes he just played the fool...don't worry =D
