Read Psalm 51 as a prayer to God from you and really repent of your sins. Repenting means never to look back and do them again, with God's help you can keep on moving forward and become a new creation in Him.
Lord give this person the forgiveness they are looking for. Give them a sign of hope that you have heard them and have forgiven them. Help them to move on with your help and to forgive them self as they accept your forgiveness. Bring them your peace, comfort, strength to come to your path and stay in it, also let them feel your love for them. May they look only for your approval and not of others for none are perfect and we are all corrupt, only through you can we be cleanse from our sins. I pray in the mighty name of Jesus Christ our Lord and Savior. Amen!