Author's Note: Written on a whim. I don't write Sakura much.
Once upon a time, Sakura had believed in God. Not in any specific holy being that you went to church for and worshipped- that was a civilian thing, and she had been raised by shinobi parents- but in a higher power that was out there and maybe helped good people once in a while when they needed it.
There wasn't any reason for her to believe so. Her parents were atheists, and so were all the other people she knew, but Sakura had always found it comforting to think that there was someone out there who was looking out for her. When Ino befriended her, she smiled at the sky. The day she found out Sasuke was in her genin cell, she spent the night staring dreamily at the stars. When she and her team got through their first C-rank mission alive, with as many close calls as they had, Sakura burnt a candle as soon as she returned home and watched as the smoke wisped its way upward to float among the clouds.
It wasn't until later, after Sasuke had left her behind to pursue power and Naruto had done the same, though admittedly for a nobler purpose, that Sakura realized who she should have been paying tribute to all along. If she had thanked Ino instead of God, maybe their friendship wouldn't have collapsed as easily as it did. If she had thanked Kakashi-sensei and Naruto and Sasuke for getting her through the mission in Wave Country, maybe their comradery wouldn't have shattered so readily, as if made from spun glass instead of the steel bonds she'd imagined.
So Sakura didn't rely on God any more to help her when she needed it. God wouldn't help her. He had never helped her. Those close to her were what had made it possible for her to get as far as she had, not something she couldn't see. And now that most of her friends and teammates were gone or estranged, there was no one left to help her but herself.
So Sakura trained. When trouble came up, she handled it alone. When Naruto returned, she didn't stay behind him. And when it was all over, she had only herself to thank for it.
Once upon a time, Sakura had believed in God. She was glad she no longer needed to.