I used to hear this song on the radio all the time. Don't actually know if it is from the 2000s but that's when I heard it loads of times.
It's a slow song sung by a girl with a high voice.
All I really remember is that she sings "quizas..." and it takes a long pause and then I think it goes "que me" and I forget the rest.
Also the song has moments where she goes "haaa, haaa, haa,..."
Really would be great if anyone could help me identify it.