He was so calm and Gamora just couldn't help but trust him. Because he was right, who was her Father to decide for the world what was best for everyone? What was best for her and her sister? Even if he had, he had decided for them but maybe that didn't make it right.
Gamora had a good sense for people with power and when Crowley told her that it wouldn't happen again, that he wouldn't hurt her. Gamora believed him. She was tired now, the adrenaline had faded from her nightmare and she yawned, leaning slowly in to rest against him.
Because there was something about him that reminded her not of her Father, but of her dad and as she closed her eyes, it was wonderful.