that theoretical knowledge and practical knowledge go hand in hand. Before the doctor cuts open the patient, he should have at least a general idea of what he expects to find.
EB certainly had from whom to absorb a theoretical knowledge of being in love-on one hand-what not to do by watching her own parents and then perhaps watching the Gardiners who seem to have a solid marriage. Then, I'm sure she read books and poetry and talked to friends and Jane and came up with hopes and expectations of what her love and marriage would be like. I've done that and I'm sure I am not alone in that.
So, perhaps her knowledge of love deepened with the experience of loving someone. She was able to discern that what she felt for Wickham and what he felt for her was nothing compared to what she felt for Darcy and what he felt for her. I also compare what she said to her father after she got engaged to Darcy about how she felt with what she said to Mrs. Gardiner about Jane and Bingley's love and (I know one should not compare apples to oranges)but it seems to me that EB had a more developed love based on mutual respect, esteem, gratitude and ardor. At the time of the conversation with Mrs. Gardiner, the love between Jane and Bingley was all looks and signs and engrossment. I don't think they spent enough time together to get where EB and Darcy were at the end. They would get there, of course, but it would take time.
I think that is one appeal of JA's novels to me. That in the end, humans connect in real relationships that are not based on physical attraction alone.