User blog comment:B00m666/Highschool DxD - Question about Issei/@comment-1359322-20131204005537/@comment-1359322-20131204095902

Actually it implied a lot in the story cause Issei only manages to confess to Rias after he overcame his trauma caused by Raynare. Well Akeno and the others were the main reason why Issei was able to overcome his fears though.