The Goddess desperately needed Shiro's help so she couldn't reject him or anything.
Heck, she was even ready to give him some rewards or benefits even if he didn't demand one, but since he did, she just came forward and told him right away - "Alright, how about I give you a skill?"
Shiro's face became expressionless. It wasn't that he was sad or dissatisfied with the reward, it was just that he was too shocked to hear it. He even doubted his ears for a second.
'Is giving someone a skill that easy?'
"…"
'I guess, it is for divine beings…'
Well, the Goddess misunderstood his emotionless face as being dissatisfied.
She immediately chipped in some other rewards as well.
"How about I give you my favor?"
'Huh?'
Shiro's face remained expressionless, this time, because of confusion.