I have to know something about you. When I know enough, or as much as I can, then I must have the faith to believe you will deal with me in a manner consistent with what I understand about you. Based on that faith, I can trust you.
No offense, but anytime you trust another person, there is risk involved. People change and fail.
In order to trust God, the same criteria are involved. You must learn about Him, and what He has done is recorded in His Word. There you can learn how He thinks and the elements of His character. (Of course God is far more complex than a person; we will never totally understand.) Your understanding of God, when fueled by the Holy Spirit will lead you to believe that He is who He says He is, and then you can start to trust Him. Trust, obey and find peace!
Trust in the Lord with all your heart
And lean not on you own understanding
In all your ways acknowledge Him
And He will make your paths straight.
Proverbs 3:5,6