sainz was raised in santander, a port city on spain’s north coast in the cantabria region. she later moved to suances, also in cantabria. "the first time i saw her, when she came, i realized her virtues. she was a girl with a lot of energy, with a lot of desire. from the beginning, i saw her a dancer,” sainz' teacher, marta rojo, told "el espanol". rojo remembered that sainz started formal dance training in 2010.