"It is a pleasure to meet you."
Translation:Estas plezure renkonti vin.
I'm not sure about the reason for it, linguistically speaking, but it is infinitive in this English sentence as well, as it is in most any other language I know of in this context. It might be because you are, as it were, talking about the act in a general sense, almost without considering yourself in the proposal: meeting you is a pleasure. That's just speculation, though. Best I can say is, it commonly is infinitive in this context in languages.