If it were impossible Jesus would not have asked us to do so. If he asked us to love enemies it is certainly possible. So pray for the grace to forgive. If we exact an eye for an eye the whole world will go blind. Jesus asks us to put love into life, to break the spiral of violence and hatred and negativity by putting love into life.
Love is the only means to achieve anything.
Jesus said to his disciples, I say this to you who are listening. Love your enemies, do good to those who hate you, bless those who curse you, pray for those who treat you badly. To the man who slaps you on one cheek, present the other cheek too .Love your enemies.