This is impossible. Please draw a bevel with only one edge.
Mathematical stuff:
Even if one side were curved, at the microscopic level it will approximate a straight line. (definition of a derivative) Whenever two lines intersect an angle is formed. Even if two curves intersect, their intersection is still an angle. In a very extreme case, let us assume one line is horizontal and the other is verticle, forming a ninety degree angle. One only has to rotate it 45 deg and you have a (very wide) bevel.