How long would it take to grow hair like giovanni dos santos hair ?

Hair grows about 1/2 an inch a month. Keep it in good condition, give your self some scalp massages to get your circulation going. Take some supplements like omega fatty acids, they are very good for you hair. Get trims every 3-6 months to allow hair to grow and mention to your stylist that you want to grow your hair out so they don't get scissor happy.