davem
I think mark12_30 is perhaps on to another aspect of this. However, I believe that the problem may lie in your interpretation of "in." I have always read "in" to refer to Eowyn's own state of being "in (puppy) love" with Aragorn rather than refering to some characteristic "in"side of Aragorn. To me that really clarifies the passage.
Of course, it is probably evident that this is the way I've read it from the tack I've taken in the thread.