The weight of both women is given to be the same, so the force applied by both on the sand is the same. But their pressures are different.
The sandal with the pointed heel has less area in contact and will therefore sink into the sand. Whereas, the sandal with the flat sole has more area so it will exert less pressure and make it easier to walk.
Hence, the sandal with the flat heels would feel more comfortable while walking on a sandy beach.