No one knows for sure how they will react at any given time. You can commit yourself, under God's guidance, to respond in a Christ-like way, taking into account that Jesus also wants you to care for your loved ones. You don't have to know for sure how you would react before deciding that you want to commit yourself to the way of peacemaking.
Pacifism is a gift.
Maybe it is a gift directly passed down by our parents. However we receive it, God calls us to accept this gift with joy.