Born in Figueira da Foz, Portugal to Kosovo-Albanians parents who originate from Dibër, Albania he was raised in New Jersey, USA. He is the son of Jill and Mergin Sina. Mergin played basketball professionally in Belgium, Spain, Italy, Argentina and Portugal. In Portugal, he was inducted into the Hall of Fame and holds the country's single-game scoring record, with 69 points in a single game. Sina's sister Jasmine is a member of the St. John's Red Stormwomen's basketball team.
Sina was three-time All-State guard who scored 2,146 points, breaking Jeffrey Dangelmajer's all-time scoring record, and handed out 861 assists at Gill St. Bernard's School. Also was four-star recruit who ranked in the top-100 nationally in the 2013 class by ESPN.com. He was three-time Somerset CountyPlayer of the Year who helped transform Gill St. Bernard's into a national power. The Knights broke into the USA TodayHigh School top 25, rising as high as No. 15 in 2012. Also played for his father, Mergin Sina, who was a two-year letterwinner at Seton Hall. He finished as the all-time leading scorer and assist leader in Somerset County history, and was second in three-pointers. As a senior, he led Gill St. Bernard's averaging 21.3 points, 9.1 assists and tallying 117 threes.
College career
In his freshman season he was Big East Conference All-Rookie Team selection, also earned Big East Conference Academic All-Star recognition. Sina was one of two players to appear in all 34 games, earning 19 starts. He started eight of the final nine games, including all three Big East Conference Tournament contests. He averaged 6.0 points, 2.4 assists and 1.4 rebounds, and led the team in assists seven times and had three 5-plus-assist games. He ranked 10th in the conference shooting 38.2% from three-point range in Big East games. He also made starts in nine of 18 Big East appearances and averaged 2.7 assists in conference starts. In 2015, Sina decided to transfer from Seton Hall due to what he called "an untenable locker-room situation." He had averaged 7.0 points per game. He transferred to George Washington, and after sitting out a season due to NCAA transfer rules, he started 34 of GW's 35 games at point guard, averaging 9 points and 3.3 assists per game. He graduated from George Washington in 2016 and rather than return for a graduate year, he signed with an agent to play professionally in Europe, which also made him automatically eligible for the 2017 NBA draft due to him leaving as a redshirt junior.
