It depends on what kind of rejection it is. Atash does not care much if it is a rejection of sharing a bed for the night, he shrugs it off. But if they reject him for any other reason. He would probably bristle, try to find out why, grump around for a bit before attempting to brush it aside the coming day. Never quite forgotten, but not too important for now.
Zemar would act more level-headed. He would be thoughtful for a while, most probably think about the 'why' before finally accepting the rejection without a huff. He's not about to throw a tantrum because of a rejection, that's not how he grew up at all.