Shirley taking an interest in Grace's beautiful hide. Yet at first, the original plot for Shirley was to take the hide from Grace and use it as fabric. But that idea was scrapped, not being threatening or strong enough for the whole story of "Coal Mine Canyon". So my new idea for Shirley's plot was to hire the Yeller Gang (old enemies from Grace's past) into snatching Grace while she has most of the town distracted by her singing performance. Then afterward, they would take a train back to Texas all the way into Coal Mine Canyon where it is Shirley's hideout and Grace would be held captive until some time when Shirley has her new ranch built and she can start breeding a herd of golden cattle. So she's likely saying these words just to put fear into her captive.