The disciples now felt that Jesus had answered their questions about where He was going clearly. This revelation helped them believe that Jesus knew what He was talking about when He taught them about God and His ways. It also helped them believe that Jesus had indeed come from God. However they did not yet understand the full meaning and significance of what Jesus had said, though they may have thought they did. Jesus had just said that they would not understand His meaning fully until a future time ( John 16:25-26). [source][source][source]
"Had the disciples really possessed the understanding they claim, they would have reacted very differently when the crisis came." [1][source]