"When Jesus therefore had received the vinegar, he said, It is finished: and he bowed his head, and gave up the ghost." John 19:30
How do you tell the person you love that you are willing to do anything in the world for them? That you are there for them through thick and thin. That you can carry their load, and relieve their pains. (Matthew 11:28) That you only want to love them with all your heart, and pray that they love others the same way. (Matthew 19:19) That they go forth and tell others about your love, and preach the good news, the way to salvation and righteousness. (Acts 8:25)
You die for them. "he humbled himself in obedience to God and died a criminal's death on a cross." Philippians 2:8 Like a lamb ready for slaughter, He died. When they did not hear anything, believe anything, receive anything, they receive that you and others were willing to deliver that message to them. They see that you loved them more than life itself, and that you died so that they might live. They see that others were willing to die because of you and your love. They see how they were willing to live in dire and destitute situations in order to spread the good news of salvation. For through Him, we are all now redeemed and the sons and daughters of the Father. 'When the centurion who stood facing Jesus saw how he had cried out and breathed his last, he said, "This man certainly was the Son of God!"' Mark 15:39 Then, hopefully, they love you back.
Love God, and love Christ.
"And see a voice from heaven, saying, This is my beloved Son, in whom I am well pleased." Matthew 3:17
He himself bore our sins in his body on the tree, so that we might die to sins and live for righteousness; by his wounds you have been healed. 1 Peter 2:24