Place the water and salt in a bowl and stir to dissolve. Add the sage, garlic, and chicken and allow to stand for 15 minutes. Remove the chicken, sage, and garlic and pat dry with absorbent paper. Heat the butter and oil in a large non-stick frying pan over medium heat. Add the chicken and cook for 5 minutes. Add the sage and garlic, turn the chicken, and cook for a further 5 minutes or until the chicken is golden brown. Reduce the heat to low and cover the pan with a lid. Cook for 4 minutes, remove from the heat, and stand, covered, for 2 minutes. Serve the chicken with the sage, garlic, and pan juices.