oh my gosh is a minced oath version of oh my god. The latter would be Oh, mein Gott! in German, the former can't be translated, but you could use a rough equivalent.
Ach, du meine Güte.
Ach, du heiliger Bimbam.
its 'oh gut'
Edit: "Oh gut" if you wanted to say it like "Oh, good." If you want to say something like, "Oh well, better luck next time," then you would probably use tja (closer to oh well in a reassuring way) or naja (pretty much the same thing but closer to well)
oh wirklich
oh nein
The German translation of Oh snap! is:Mist!Verdammt!
English: "oh" is German "o". Chrismas song: "O du fröhliche, o du selige ..."
Oh je, deine Hosen brennen.
really - wirklich
ANSWER Ach, mein Gott!
I am really in love with you is Ich bin wirklich in dich verliebt in German.
Irish - i ndáiríre?
If you mean really as in very, i.e. He is really stupid, the you say tres. If you mean really as in "Is that true?" or "Oh, really?", then you say c'est vrai?
Ja, wirklich.
Really as in: Wow, really? is "wirklich" Really as in: That's really cool. is "echt".
íDe verdad! íDe vera!