Peter believed that burying the emotions probably saved her as a kid, but they were just buried and not gone. His mom had always told him that emotions made you stronger and even when he'd been mad at her for dying on him he believed her. But he didn't know how to help Gamora with dealing with having and showing feelings. He got himself, he didn't know how to help others with it.
"I'll make you a bowl." He counted it as a positive step she was letting him give her some cereal. It made him glad he'd picked a normal type today instead of Lucky Charms. It didn't take long to grab a bowl to pour out some cereal and add milk before he handed it over with a spoon. "There you go."