How are we supposed to forgive someone after they have hurt your heart beyond repair?
  Jesus teaches us to love our enemies, to do good to those who harm you, and forgive those who have sinned against you. When Jesus was teaching how one should pray he said, 
                     

“
And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by men…Butwhen you pray, go into your room, close the door and pray to your Father, who is unseen. …This then is how you should pray: 

         ‘Our Father in heaven 

           hallowed be your name, 

            your kingdom come, 

            your will be done

            on earth as it is in heaven. 

            Give us today our daily bread and forgive us our debts, 

             as we also have forgiven our debtors.

             And lead us not into temptation, 

             but deliver us from the evil one.

For if you forgive men when they sin against you, your heavenly Father will also forgive you.
  But if you do not forgive men their sins, your Father will not forgive your sins.” (Matt.
  6: 5-15)

How does one go from being bitter and resentful towards a person who has crunched your heart up and left you feeling betrayed and worthless, to a point of healing and forgiveness?
  What is the practical, day-to-day application?
  It says in Romans 12: 2 “Do not conform any longer to the pattern of this world, but be transformed by the
renewing of your mind.”
  And I think therein lies the answer of how we as Christians and human beings, can overcome the point of bitter resentment, and cross over to healing and forgiveness.
  By the daily renewing of our minds.
 

 

“And when you stand praying, if you hold anything against anyone, forgive him, so that your Father in heaven may forgive you your sins

,” – Mark 11:25 
 

Our mission as Christians is to become more like Jesus, imitating His life on earth and obeying his commandments.
  God’s beautiful character is shown through the poetic words of King David in Psalms 103:8-10 –

“The Lord is compassionate and gracious, slow to anger, abounding in love.
  He will not always accuse, nor will he harbor his anger forever; he does not treat us as our sins deserve or repay us according to our iniquities.”
 

Let us then forgive one another as we also have been forgiven by Jesus Christ Son of the living God, and God the Father, Almighty and ruler of all creation.
  With forgiveness comes healing.