Saving faith means trust, reliance, dependence and confidence in the Savior and what He did on the cross for salvation.
It is to be wholly and entirely confident that what the Savior did on the cross was enough and sufficient for one's salvation. It is resting on the worth of the Lord Jesus Christ and the work He did on the cross.
If the Lord Jesus Christ and His work on the cross for the sinner's salvation were a wall, faith leans on it entirely.