When a planet or moon is tidally locked, the same side always faces the object it's orbiting because the rotation and orbiting of the object just so happens to be so perfectly aligned, 1 side of the object always faces the object it's orbiting.
When a planet or moon is tidally locked, the same side always faces the object it's orbiting because the rotation and orbiting of the object just so happens to be so perfectly aligned, 1 side of the object always faces the object it's orbiting.