Zumba Fitness Rush

I feel the easiest song to earn this achievement with is "La Matanga" It is a medium intensity warm-up song that doesn't involve any crazy moves. Remember that the pink box will pop up in the upper right hand corner preparing you for the next move. Also, listen to the music as that will cue you to the rhythm and the next moves. Don't worry so much about shaking your body, focus on moving with the instructor to the beat and you will get 5 stars no problem!

Much more easier then "La Matanga", i found "I Know You Like It", a Hip-Hop Song in the Zumba Dance Stuido.
The song is very easy because you don't have many moves, where you need to focus on legs and arms together and there are just around 7 different moves in this song, which are all very familiar.
The beat guides you very well through the song.

I got the achievement in my second trie so you should have no problems getting it.

You have to select a "Single song" with the correct intensity. Even if you get 5 stars on a song in a class this achivement will not pop. Here is the list of High intensity songs you can get this on. Just find a song you like and play it a few times once you have the basic moves down they repeat alot so as long as you can keep getting "Zumba" ratings you should reach 5 stars

Medium Intensity songs
Chillin Bombon Guajira
Contigo
El Batazo
Hindu-Cumen
I know You Like It
I Wanna Move
La Matanga
Lo Que Traigo
Mi Vecina
Pause
Perro Amor
Que Ta Pasa
Quebra As Cadeira
Salsa Sabrosa
Sukumbiarabe
Tigre
Un Solo Pueblo
Vem Na Zueira