The ornamental design for a bentstemware, as shown and described.
FIG. 1 is a front perspective view of a bent stemware showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines in the drawings depict environmental subject matter only and form no part of the claimed design. The dash dot lines in the drawings represent the bounds of the claim and form no part of the claimed design.