"The only correct one."
Translation:Το μόνο σωστό.
In Greek we say "Το μόνο σωτό." which is correct. However, in English we need an object after "correct" eg "The only correct answer." if we don't have anything specific we add "one" or maybe "thing" etc.
*But you can never add "ένα" translating "one" at the end of the sentence. Only if there is another word as a subject
That's right each language must maintain it's correct form. Sometimes they resemble each other but very often the expressions are very different so we need to pay attention to how each language expresses things.