If you make NT$ 14,000,000 a year living in Taiwan, you will be taxed NT$ 6,270,611. That means that your net pay will be NT$ 7,729,389 per year, or NT$ 644,116 per month. Your average tax rate is 44.8% and your marginal tax rate is 60.0%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of NT$ 100 in your salary will be taxed NT$ 60, hence, your net pay will only increase by NT$ 40.
A NT$ 1,000 bonus will generate an extra NT$ 400 of net incomes. A NT$ 5,000 bonus will generate an extra NT$ 2,000 of net incomes.