Upvote:-3
Being half-God could have give him a unique ability to resist sin that us mere mortals do not have.
Upvote:1
The following is a Trinitarian answer. Jehovah's Witnesses, Unitarian, or LDS (Latter Day Saints) will have a different answer, so I will edit / delete this answer when scope is added to the Question.
Jesus managed to remain sinless because his human nature is "full of grace and truth" (John 1:14b), possible because he was first God's Logos (John 1:1-2) who "became flesh" (John 1:14a), meaning that God's essence took on human form in the person of Jesus. Jesus as God is of course sinless, and because the grace of Jesus as God (i.e. the Logos) flows in full to Jesus's human nature. Jesus's human nature empowered by the full grace of the Holy Spirit was then capable of being sinless, meaning that Jesus had the perfect will to conform to God's goodness at all times while on earth.
But our will is not as perfect, being marred by the Fall; our psychology is messed up since birth. Although Jesus DID face all kinds of temptations that we also face (including high spiritual temptation recounted in Matt 4:1-11) he didn't succumb into sin, even when at the prospect of crucifixion he was tempted to withdraw from fulfilling His mission to save us on the cross (Matt 26:36-46). For this reason Jesus was deemed fit by God to save us if we are at least WILLING to be united with Jesus through faith, enabling Jesus's divine life to help us fix our brokenness.
For more on this, hear the segment "Could Christ have sinned" from the Church Grammar interview with Fr. Thomas Joseph White on Tough Christology Questions minutes 19:50 - 25:28.
P.S. It's wrong to say that Jesus is "half-God". Most Christians see Jesus as fully God and fully Man, according to Chalcedonian Definition.