Yes, God is faithful. The Bible tells us in Lamentations 3:22, 23,, "It is because of the Lord's mercies that we are not consumed, because His compassions fail not. They are new every morning. Great is Thy faithfulness."
God has been with me every moment of my life. He is faithful to guide me, to provide for me and to protect me. One of the greatest evidence of His faithfulness is His forgiveness for my sins. 1 John 1:9 reminds us that He is faithful and just to forgive us for our sins and to cleanse us from all unrighteousness.
I think you have to experience God for yourself before you can fully understand His faithfulness. You have to have a close relationship with Him to appreciate the way He works in your behalf. If you do not have faith to believe in His existence and in the loving way He works in your life, chances are you will not understand His faithfulness.