Onesta was the daughter of unknown parents. The date and place of her birth have not been found.
Her husband was Guglielmo I della Scala. They were married, but the date and place have not been found. Their eight known children were Brunoro I (?-1437), Antonio II (?->1412), Nicodemo (?-1443), Paolo (c1387->1441), Fregnano (?-1443), Bartolomeo (?-1433), Oria (?-?) and Caterin (?-1423).