Ask in HeartFaith which is not weakened by unbelief Mar 9:24.
HeadFaith is the starting point but it is always tempered by doubt and unbelief.
Jesus talked about continuing in His Word and keeping His Word Joh 8:31 Joh 14:23,24.
Faith must move from your head into your heart in order to appropriate the provisions of Grace.
Being able to operate in HeartFaith is a function of your mind being transformed to the MindOfChrist Phi 2:5.
Jesus believed every Word that came from the Father`s mouth Mat 4:4 and so must we in order to operate in power and authority as He did Joh 14:12.