User blog comment:Xhatefate/DxD Updates~/@comment-201.239.133.207-20161205193959/@comment-10330822-20161220221219

Well, she still could have swooned after hearing about. Hearing a boy your age standing up to Super Devil and Satan-Class devils and evil dragons to protect your homeland is pretty impressive. Also, it could have simply woken her up to the vampires not being as special and untouchable as she may have thought.

Also, when it came to Ravel. She explains later why she was so impressed by Ise against Riser. In other words, there was a story behind her feelings, something from her early life. It was the stories about princes and knights rescuing princess and stuff that made her so impressed by Ise, because it reminded her of the stories she heard as a little girl.

In other words, the reason Elmenhilde fell for Ise may be something similar, a seemingly unimportant action may have sparked her interest in connection to something in her own past.