To get the desired outcome in golf, what two things have to be in sync?

The answer would be: Your hips and your shoulder (your core and upper body).

In order to give a best shot possible, it is important for every golfers to generate enough power from their swing to a controlled direction.

This kind of thing can only be achieved if your move your hips and shoulder on a synced & balanced motion with a correct type of golf sticks.

You might have seen people playing golf in person or maybe in movies. You must have noticed that people have to learn and maintain proper posture as they swing their golf club. The key technique for administering a strong and swift impact is in your spinal column. Since golf swinging is a turning motion, the technique is to smoothly turn your body about the central column, which is the spine. To do this, you must keep the areas of your body on both ends of the spine in sync, so that your spine is kept straight. These areas are the upper body in the shoulders and the middle part of the body where the spine ends, the hips. As long as you keep the shoulders down to the hips straight and in sync, you would be able to hit the ball efficiently.