When someone betrays someone they love dearly even when they occasionally loathe them, their love may still be the overriding emotion. Hatred, on the other hand, will be a much stronger emotion than love if one does not love that individual.
Ernesto hated and loved Reshimin at the same time. he tought both emoions was equal but themore he stick with Klay the stronger his love become. He doesn't like being dominated but missing her is making him feel like surrendering.
Klay who'se clueless of the things running on Ernesto's head continue praying in front of the world tree while Ernesto just stayed still while he looked down at Klay.
It took Klay longer to make the tree talk to them so Ernesto was about to let go of Klay's waist but Klay pulled his hand and he ended up back hugging her instead.
Looking up to him, Klay said, "Don't let go."
Erensto just nodded and just listen to Klay's prayers that sounded like a lullaby than a chant.