Marta's liberation
This movie is fantastic for its subtlety. So much is left for the viewer to interpret and speculate. There are especially 3 points that are left to the imagination (1) what did Jacobo give Marta as a present at the end of the film, (2) what happened between Marta and Herman in the hotel room, and (3) what did the note to Herman say. Obviously, no one can say for sure, but I do not believe that Marta and Herman started up some sort of affair in Piriapolis and that she then ran off to be with him in Brazil. Remember that Herman was already married with teenage daughters. I suspect that his wife is still in the picture because of the phone call Marta got when she was in Jacobo's apartment. The voice on the other end was speaking Portuguese. Also, I think that Marta was too old for that kind of frivolity. She yearned for romance, but I don't think it would have been in her character to run off with a married man.
The hotel room: I think that Marta told Herman that the marriage was a sham when she visited Herman in the hotel room. I think she also told him that she wanted to go to Brazil, not because she wanted to be with him necessarily, but because she wanted to get out of her current life. I suspect this because after the hotel room scene, Marta tells Herman in the pastry store that if she could travel, she would like to go to Brazil. This would not make sense to Herman unless he KNEW that she had never been there before. Recall that Jacobo and Marta lied to Herman that they spent their honeymoon in Brazil. But Herman does not question her when she says that, which suggests that he knew that the honeymoon story, and the marriage, was false.
The gift: I think that Jacobo gave Marta money. He intended to do that all along, even though Marta declined it. This is supported by the fact that the Jacobo won a large sum of money playing roulette. It was the only time he cracked a smile during the whole film. The package looked like it could contain a large sum of money, and I think that Marta confirmed her decision to leave when she received it. Watch her expression in the cab as she is riding home holding the package. The gift is her key to freedom.
The note: This is the most obscure part of the film. What did that note say? I suspect it said something to the effect of "I'm leaving Jacobo's business and leaving Uruguay. I will be travelling to Brazil and will look you up when I get there." Alternatively, it could be a "Thank you." It must be something that Marta did not want Herman to know about until it was too late for him to communicate it to Jacobo.
These are only possible interpretations. I would like to hear other people's. Isn't it great when you can debate these kinds of subtleties from a film? So refreshing from the usual American-made trype.