The strange response

The response to the apostles today strikes me as strange. Jesus has just finished explaining how even if someone wrongs you seven times in a single day, if they apologize, you are to forgive them, and the response of the apostles is to ask for faith. Jesus tells them faith isn't the issue, when he says "If you had faith the size of a mustard seed..."
It strike me that the real issue in this kind of forgiveness of repeated sin is neither faith nor love, but the third theological virtue, hope.
When some continues to do the same thing over and over again, we loose hope. We begin to believe that they will never change, or worse yet, they can never change. We loose all hope. In a word we despair.
Despair in Christianity is considered a sin. Why? Because it is a denial of the power of God, and Grace.
Science tells us that our physical self is in a constant state of change, even after we die. Our faith tells us until the very last nanosecond of our earthly life, conversion to God is possible.
As long as God exists there is always hope.