If you dreamed that you were in a coffin: You should choose the right one, there may be agreements on matters that you believe in your heart. To see that you are in a coffin in your dream indicates that the person who sees the dream will live a happy and peaceful life, will have a long life and will raise good children, will give the necessary importance to his parents and will take their blessings.
To see that you are in a coffin in your dream means a life that will pass in wealth, abundance, pleasure and happiness.