They did not go to the tomb believing in resurrection.
The fact that they took burial spices along with them to anoint the decaying body tells us what their expectations and mindset were. Even after Jesus had given them six solid advance resurrection directives, they still came prepared and expecting to use ancient spices and juices to embalm the dead and lifeless body of Yeshua – the Christ.
They did not go to the tomb of Jesus expecting it to be empty.
They were surprised and astounded at what they saw, or did NOT see. They were even skeptical and disbelieving of the resurrection of Jesus when they heard later that morning that the tomb of Jesus was empty. In fact, based on the reactions recorded in the Gospels, it appears that it was the last thing they expected. It was the beginning of the Resurrection of Jesus paradox.