"Η αγάπη είναι το καλύτερο συναίσθημα."

Translation: Love is the best emotion.

[mcampanella]

I thought καλητερο was the comparative, not the superlative. Was I wrong?

[mizinamo]

• καλύτερο = better
• το καλύτερο = the best

The modern Greek superlative is the same as the comparative but with the definite article in front of it.

(This means that it's ambiguous with "the" + comparative -- το καλύτερο could also mean "the better (one)".)

[Alexhatzopoulos]

To add: there is a form of the superlative that is different, "-τατο," but as far as I can tell it is less common than just using the comparative. Further, there is the irregular superlative of καλός which is άριστος, which may be a little archaic but I think is still used pretty well.

[mizinamo]

As far as I know, that form is an elative or absolute superlative in modern Greek -- something like "very good, very high" etc. rather than "the best, the highest", etc.