The AncestryDNA test will not tell you which Cruse ancestor you descend from. It gives you matches with your genetic cousins on all your family lines. The test works best for finding matches within the last five generations. How far back is your Cruse ancestor?
If you wish to verify your Cruse lineage you need to arrange for a direct male-line Cruse descendant to take a Y-DNA test. I am running a DNA project for the surname Cruse and variants including Crews, Cruise and Crewse as part of my one-name study research. You can read about my one-name study on my profile page on the Guild of One-Name Studies website:
http://www.one-name.org/profiles/cruwys.htmlPerhaps if you share with us details of your Cruse lineage we might be able to help.