"You are truly a nice couple."
Translation:Siete proprio una bella coppia.
If anyone is interested ( slightly off topic), the word "nice" originally meant delicate/intricate/ refined/ well made. A hundred and something years later it has now been so over/ misused that it is extremely vague/ bland, meaning " quite pleasant/ OK/ attractive etc". It is so bland and virtually meaningless we were told to never use it in wrtten English as there is always a better more precise word.
So far you've learned two different types of proprio. If you can identify the role of the word, then you can figure out whether or not to use a different form :)
adjective indicates possession: like most adjectives, this one does change with gender and number
- Ognuno ha la propria giacca/Each one has got his own jacket
- La ragazza usa i propri poteri/The girl uses her own powers
adverb can mean truly/really...: like all adverbs, this one does not change
- È proprio una bella giornata/It is truly a beautiful day
- È proprio un disastro/It is truly a disaster
Most of the time they come after. The ones that commonly come before are bello, buono, grande - all with their various derivatives. Also worth bearing in mind is that the position of the adjective can change the meaning eg una borsa cara = an expensive handbag, un caro amico = a dear friend.
Dome further detail: Demonstrative adjectives (questo and quello,) posessive adjectives (mio, tuo, suo) and Indefinite adjectives (Quali and Quanto) always go in front of the noun. To just about complete the set also remember ogni, qualche and nessuno. Hope this helps.
As a native English speaker, I can't explain the Italian grammar with any certainty, but I suspect it's because the "you" is implied to be plural--as though you are saying, "You (two) are truly a nice couple."
I don't know, though, whether Italian counts the couple as a singular collective noun when we speak about them in the 3rd person--as in "That couple is truly nice."
We have the word "proper" in English, which means "real", so if it helps, you could think of "proprio" as meaning "really" (as in "you're a really nice couple") and "veramente" as "truly". In some English dialects, there's the expression "proper", which means "really" or "very", as in "you're a proper nice couple".
Thanks for looking at my profile. It is confusing doing several languages at the same time, especially if they are from the same family (Germanic or Romance for example), but I had a bit of a head start - my German is fluent and my French conversationally fluent. Then I found it was best to concentrate on one at a time, so I'm not working on my Italian at the moment, just Dutch, having spent the last year concentrating on Danish.