User blog comment:B214/Volume 23 discussion blog/@comment-77.46.204.73-20171109100644/@comment-3285616-20171112114520

^Precisely. If you read the Light Novels, straight after Issei's trauma has been lifted and he confessed to Rias, it's clear that he has become more perceptive to the girls' feelings. Even other minor things like how he begins to call Rias by her name,  but still stutters, even in his thoughts. It's small details like this that makes the LN so enjoyable. I loved the way Ishibumi did this concept and it wasn't just a throwaway thing. After a while she calls Rias by her name without any hesitatation.