Well to be fair, one refuting sentence said to someone who thinks what she said, isn’t going to make her change her mind.
But I know the type of person you’re talking about. It tells me either she is either just filling a seat every time she happens to go to church, or the pastor there is not sending out the proper message, or at least not effectively.
In such situations (and they are Legion) Lutherans trust Luther's explanation of the Third Article of the Creed that the Holy Spirit "produces faith when and where He pleases
It is a mystery that we will not understand until the last great Day of why there are what appear to be many times when productive faith just doesn't seem to please the Holy Spirit.
I said a lot more than that sentence, about that subject. We debated the topic for about a half hour.