Jesus' words are quite clear - if we remain in Him and His words in us, we can ask whatever and it will be given. At the end of this conversation, Jesus says that we are to bear fruit - fruit that will last. THEN the Father will give whatever we ask in Jesus' name. Jesus basically gives us a blank cheque, to ask whatever and it will be given. But, this blank cheque is tied to our wills being aligned with God's will, and to our character bearing fruit.

John 15:7 and John 15:16