ChocolateFactory

I'm currently planning a trip to some place warm for New Year's.
Ideally somewhere safe with great beaches/resorts, views and nice bars and restaurants.
Last year, my girl-friend and I went to Puerto Rico, and that was great.
At the IC for example, we could spend the day on the beach/by the pool, and then go to the old town of San Juan for the evening, where they had great food and people were dancing salsa etc.

For this year I got lucky and found a cheap award MAD-GRU for December 27.
I haven't been to Central/South America before, so I thought I could use the opportunity to go to Rio de Janeiro, and maybe Buenos Aires.
But from what I've heard, neither place has nice beaches, and especially Rio isn't really safe.
So I was thinking about maybe doing 2 days in Rio, 2 days in Buenos Aires, and spending 4-5 days somewhere else just relaxing.

The only challenge here seems to be that award availability is currently quite sparse and everything is so far apart.
Where would you go? Which places would you recommend for a first time visitor?
I'm not a big fan of hiking by the way (especially not in the heat), I want this to be nice and relaxing, but I don't mind walking around exploring a city or maybe going on shorter hikes (1-2 hours).
We like good food (steaks, seafood, ...).
My girl-friend speaks some Spanish, I don't, in case that matters. Neither of us speaks Portuguese.

Any destinations you would recommend?
Maybe it's not such a good idea to fly to GRU after all (but the flight time is so good, and the award was so cheap...)?

Thanks!