La fille là-bas !

While we all joked around in French using vraiment for all of our really needs, we never figured out how to actually say the really we were looking for.

Let's address the really that we substituted with vraiment, or what I'll be calling really?. This one is pretty simple, although the direct translation finds no home in English:

Ah bon? = Really?; Truly? (if you're aiming for formal (don't expect to be taken seriously))

"Il faut pas manger des oeufs crus; tu peux tomber malade !"
"Ah bon ? J'en savais pas."
=
"Don't eat raw eggs; you could get sick!"
"Really? I didn't know that."

The next really is the really of really, really something. While très is totally correct, it is being used less and less (at least among the youth) and is being replaced by trop:

"Merde ! T'es trop vite !" = "Shit! You're really (lit. too) fast!"

This can also be replaced with tellement: "You're so fast!"
It helped me remember how to use tellement by breaking it down literally: such-ly.

That brings us to the really that really means actually.

"Il a dit qu'il allait au hypermarché, mais en realité / en actualité / en fait il est allé chez sa copine !" = "He said he was going to the hypermarket (think Wal-Mart, but not as hell-bent on the destruction of mankind), but really/actually he went to his girlfriend's!"

yess

I'll sum it up with a significantly more slangy version of really. Yeah... yeah vache means cow, but vachement is normally translated as real in American English and bloody in British English, but I don't think it's vulgar. At least I hope not.