Mark 16:11 "But when [His disciples] heard that he was alive and had been seen by [Mary Magdalene], they would not believe it."

Mark does not say that the disciples "did not" believe, but that they "would not". This is a question of will. Of course one can understand why it would be very difficult to believe that someone had come back to life after being brutally killed, but if that was the case you would say they "did not" believe. The word choice is important, it means that the apostles were still prideful and stubborn. They refused to believe, even though they had seen Jesus raise Lazarus from the dead, so they knew it was a possibility. It probably did not help that it was Mary Magdalene who saw the Resurrected Jesus first and not one of them.

When I think of the humanity of the apostles it gives me hope. They were not perfect. They had the same biases and tendencies toward pride that we all have, even after spending three years with Jesus. Jesus did not let that stop that Him from calling them to their mission, and loving them every step of the way (although He did upbraid them "for their hardness of heart" in not believing. Mark 16:14)

The disciples "would not" believe Mary Magdalene, but Jesus would be sure to give them all the proof they needed to see that His Resurrection was real. When Thomas missed Jesus' first appearance in the Upper Room, he repeated the same mistake, saying he would not believe unless it was proven to him, so Jesus proved it to him. (John 20:24-29).

We are all weak, we all have blind spots and stubbornness in certain areas. Jesus will work around those when He has to. He will get us to the place we need to be to complete our mission. He will overcome our fear, our pride and our stubbornness if we allow Him to, and that is very reassuring.