"Do not fear, only believe." - Mark 5:36b ESV
Another way to translate this is 'Not fear only faith'. The words is Monos (Strong's G3441) and it means to stand alone without a companion.
"For this reason I remind you to fan into flame the gift of God, which is in you through the laying on of my hands, for God gave us a spirit not of fear but of power and love and self-control. Therefore do not be ashamed of the testimony about our Lord, nor of me his prisoner, but share in suffering for the gospel by the power of God, who saved us and called us to a holy calling, not because of our works but because of his own purpose and grace, which he gave us in Christ Jesus before the ages began, and which now has been manifested through the appearing of our Savior Christ Jesus, who abolished death and brought life and immortality to light through the gospel," - 2 Timothy 1:6-10 ESV
Not fear only faith because of grace.