Paz Vega was miscast... forget about her physical appearance
She's a lovely lady and has done so much better in other films (Like "Lucía y el Sexo") but shs didn't do a good job in this movie at all, I didn't buy for a second she was a Mexican woman. And all the people praising her accent are either deaf, ignorant or delusional. She sounds like a woman from Spain, her accent isn't mexican at all. And this is very distracting
The differences between the two accents are more than just the way we pronounce the Z, the C, and the S. There are very little details that Paz Vega simply chose to ignore. In contrast Oscar Jaenada was much better playing Cantinflas