Fainu started at prop in the 2021
Harold Matthews Cup winning side, including scoring a second-half try in the Grand Final win over
Parramatta Eels. Fainu earned a promotion to
Manly’s SG Ball Cup (Under 19s) team in 2022, making seven appearances for two tries, two try assists, four line-break assists, 13 offloads and 150 tackles (21.4 per game). Fainu pushed ahead to the
Jersey Flegg Cup (Under 21s) later in the year whilst still eligible for Under 19s, playing seven games with three tries including a double on debut in round 14. Fainu made the NSW Under 19s squad in 2022. Fainu made his first grade debut from the bench in his side's 12−6 victory over the
Wests Tigers at
Campbelltown Stadium in round 8 of the
2023 NRL season. In July 2023, Fainu signed a four-year deal worth $2 million to join the Wests Tigers ahead of the
2024 NRL season. Fainu made his club debut for the Wests Tigers in round 2 of the 2024 NRL season against
Canberra. Fainu played 23 games for the Wests Tigers throughout the 2024 NRL season as the club finished with the
Wooden Spoon for a third consecutive year. == Statistics ==