Supernatural 4.14: Sex and Violence
Sam: Dean, look, you know I didn't mean the things I said back there,
right; that it was just the Siren's spell talking.
Dean: Of course. Me, too.
So it's absolutely clear at the end of Supernatural 4.14 that Dean is
lying to Sam and that he knows he is lying to Sam when he nods
agreement that his words and actions were the Siren's spell speaking.
The interesting case here is Sam.
Unlike Dean, Sam has been lying for years about his identity - and
he's done it so he won't have to deal with others learning the truth
about him and thinking he's freakish. He did it categorically when he
was at Stanford and now he does it to keep Dean from learning the
truth about him and thinking he's freakish. In other words, he does it
for self protection. Which makes it different from Dean whose
significant lies, for the most part, are made to others in order to
protect them from truths they can't bear.
OTOH, Sam was born under a bad sign. And the fact that he sometimes
needs privacy to deal with issues that have been forced on him and
were not, in origin, of his making, is also undeniable.
Sam is the one to begin the apology at the end of 4.14. And he does it
in his sincere voice, with his face sincere and his eyes sincere. I
think the only question here is is he trying to convince himself or to
convince Dean? Or is lying so ingrained in his psyche now that he
believes his lies as he is saying them?
Dean doesn't buy it for an instant. Every word he uttered was right
from his heart and he knows that this is true of a part of Sam as
well, a Sam we have caught glimpses of throughout the seasons. But
since under the Siren's spell he tried to kill Sam, he hardly feels he
has the right to call Sam on anything, and it's just not his style to
confront the problematic emotional stuff with talk, but to sit on the
problem, hoping the impulses will fizzle out, before it explodes.
Sam learns the truth about what he said in Dean's eyes, when Dean,
too, agrees with his assertion and it's absolutely clear Dean's lying;
because Sam then knows that Dean knows he's lying, too, and just
doesn't want to talk about it directly, since that might cause their
fraying fraternal ties to break clean away.