User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-104.7.80.176-20150603035954/@comment-26209278-20150603063432

Think they kind of forgot the effect the whole event had on Issei, until they had that touching moment in vol.10. Think she fell for him the same reason everyone else did; she saw how kind and caring he was, developing feelings during vol.2, and after the Raiser RG, completely fell for him.