What is meant by Madinah is a place of safety? And the one who sins therein is cursed? But how is it possible for one ti never sin if i live there ? Will i be cursed?

No, the curse is not for every sin committed there. Shaykh Ibn Uthaymin said it is for one who introduces an innovation in the religion or stirs up fitnah among the Muslims, and that whoever commits a sin in Madinah does not fall under this threat, though a sin there is graver than elsewhere.