Many LD people do not understand this, especially I would say LD women. However, I am convinced you have other issues at play here that are affecting her SD.
As far as asking her to define "passion", it's a fair question of course for you to ask...but often it's very difficult to define "passion" for some people. I realized that myself when trying to explain it to my H. Especially when I realized that my definition of "passion" wasn't the same as his.
I would challenge you to stop accepting shrugs and "I don't knows" as an answer though. Let her know that you are more than willing to do what she needs, but it's up to her to tell you what that is in specifics. If she doesn't do that then she cannot put it off on you that you don't meet those needs...you cannot read her mind afterall.
