Texas-Louisiana border river
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">texas-louisiana border river</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sabine that I've seen before include "Inhabitant of ancient Italy" , "Old Italian" , "Italian tribe" .)