Jesus helps us with our problems by turning our sorrow into joy.
Jesus did not say in verses 16-22 that the disciples sorrow would be replaced by joy, but it would be transformed into joy. We may be going through troubles now, but with Jesus, joy will come.
For our light affliction, which is but for the moment, is working for us a far more exceedingly and eternal weight of glory! 2 Corinthians 4:17
Jesus helps us by giving us awesome prayer power in his name.
When we ask for things in Jesus' name, we ask for things that are the will of God. We don't ask for selfish things, but for things Jesus himself would have prayed for.
...Ask and you will receive, that your joy may be full. John 16:24
Jesus helps us by not forsaking us when we falter.
When Jesus was arrested in Gethsemane, most of the disciples fled, but Jesus did not give up on them! Any of us can be faithless at times, but even if we fail the Lord miserably, He remains faithful.
If we are faithless, He remains faithful. 2 Timothy 2:13
...In the world you will have tribulation, but be of good cheer, I have overcome the world! John 16:33