I've read a bit of what people have said about 4w3s on this site and most of it was contradictory and confusing. I based my typing off descriptions from other places that seemed a bit deeper and... kinder, somehow.
And I agree with what some of the above posters have said, that 4w3s have ideals set for themselves, and I can only talk about myself, obviously, but I think in some ways the longing itself has more meaning than actually reaching any of those ideals. I've read about contradiction being a theme with 4w3s and I think it's true. The intensity of feeling and the need for expression versus the fear of what destruction expression might cause. Control versus lack of control. But I don't think that with 4w3s there's a "real" person hiding underneath, or anything like that. It's all real. I've realized that as I've become more comfortable with myself I've become far more more comfortable being around other people, and I think that the fact that I am louder, friendlier and more sociable around others isn't part of some sort of split in personality or forced inauthenticity.
Oh, here's what I read (about contradiction): 4w3s are marked by multiple dichotomies due to types 3 and 4 being opposites in so many ways: inferior/superior, being/becoming, self-conscious/confident, putting themselves down/glorifying themselves, withdrawn/assertive, emotional/flatlined, reactive/cool-headed, mired in the past/focused on moving forward, awkward/poised, fragile/resilient, easily discouraged/do whatever it takes, rejecting the game/conquering the game.