I'm sorry that the adolescent ravings of the previous reviewer appear first. His profound failure to "get it" is an embarrassment.
First of all, this is about a young man of "white-bread" heritage casting aside all he has and all he is, even leaving the love of his life for two and a half years, in order to immerse himself in a culture about which he is totally ignorant so that he can offer them the greatest gift he has to offer: His faith.
Rather than "looking down" on the people he has come to SERVE, he bears great hardships, and exerts himself in ways he could never have conceived, in order to connect with these people. He comes to love them, profoundly.
And their love for him in return, even those who have reason to be suspicious of him, is a testament to his sincerity.
Please recall that this is a TRUE STORY. Whatever you might think of John Groberg's religion, or his motives, the fact is that these things actually happened in just this way. He DID travel from Idaho to Tonga, he did live among the people there, he did come to gain their trust, he did bring to them a precious gift of faith, and he did return often throughout the rest of his life, with his wife and family, to be among these people whom he loved.
That anyone could be so callously dismissive of this truth is a sad commentary on our "post-Christian" society.
But I found this film to be deeply moving and very satisfying, and I recommend it highly to those who enjoy inspiring film.