"The Protestant influence on modern ideas about religion has made sincerity and good intentions defining features of good religiosity"

That's from this article on religion in the movies of the Coen brothers.

It's an issue that has interested me ever since my first girlfriend criticized members of her church who had memorized the creed and recited it by rote. She thought it meant nothing unless they read it and thought about the meaning of each phrase as they said it. She was an Anglican girl of a low, or Protestant, bent. She'd been a very pious girl who taught Sunday school but had already begun to drift away when I met her. She had a copy of Foxe's Book of Martyrs on her bedside table.

The fact that I know what was on her bedside table is not as incriminating as it might seem. She had very little in the way of parental supervision, her mother had died and she and her father had become somewhat estranged in the aftermath following a very difficult death. But even left alone to socialize in any room of her house, with no one else under the roof, we were shockingly innocent.

We were, however, headed in different directions. She was ion her way to losing her faith and I, a cradle Catholic but not terribly convinced, was on my way to finding mine.

That experience is not, in itself, enough to cast doubt on the value of sincerity in religion. It takes a lot more. That said, I think the evidence is there to do it.