Final answer:
Nathanael initially doubted Jesus because He was from Nazareth, but after meeting Him, Nathanael recognized Jesus as the Son of God.
Step-by-step explanation:
When Philip told Nathanael that they had found Jesus, Nathanael's response was initially skeptical. He asked, "Can anything good come out of Nazareth?" However, after meeting Jesus, Nathanael's doubt vanished and he declared, "Rabbi, you are the Son of God; you are the King of Israel." This interaction is recorded in John 1:45-49.