For some of us faith seems to come easy, but for others it comes hard. Some people need more evidence than others. We see this not only in this passage, but also in Jesus' dialog with Thomas after His resurrection, and in the conversion of Saul, who later became the Apostle Paul.
There is a tendency for each to look down on the other. One may impatiently see the other as stubborn, arrogant, and willfully blind to truth. Those so accused may counter that the other is ignorant, gullible, and stubbornly blind to truth. An endless struggle...
But it must be remembered that this man was standing in front of Jesus. He wasn't there with anger, hatred, or malice like some others who Jesus handled differently. His presence was evidence he was open to the possibility that Jesus may be who and what He claimed.
Jesus simply verbalized his observation about the man, then provided the evidence. The man saw the initial evidence, then, still unconvinced, questioned the evidence further, and finally believed. This led to the conversion of his whole house!
Where will the interested skeptics come for evidence? They will come to Christ's followers. May Christ Jesus give us patience, and use us beyond our ability.