The cross is proof of God’s love for all mankind. It is enough that Jesus died and that he died for me.
But without faith it is impossible to please Him, for he who comes to God must believe that he is, and that he is a rewarder of those who diligently seek him; Hebrews 11:6.
Do you trust God, love God, and respect God? If not, something is missing in your life. There are people who maintain that they would believe in God if he proved his existence to them. But if trust in God is lacking, no amount of proof would be of any use.
Even if there is no trust in God on man’s part (you), it is not because God does not love us. It was sin on our side that put an end to man’s relationship with God. The cross (bridged the gulf between God and man) is proof of God’s love for you and me.