After a good discernment, there is peace and I think there is the joy in knowing that one has truly sought to know what God wants and choose that. Remember it is always between two good things.
Sometimes it is too hard to discern when your heart is saying one thing and your head another. Maybe that is when you need to be patient. Pray for light and it will be given to you.
I remember when I first asked a Jesuit about my vocation to religious life, he suggested I write down on one side of a piece of paper all the reasons for and against it. Well, I had many reasons on the side of the paper that was against entering the convent and only one on the other side. However that one was that I thought Jesus was calling me and wanted me to be a nun; I had all these reasons of what I wanted - to marry and have lots of children being one of the strongest against being a nun, but God's wanting this for me seemed to outweigh all the other reasons.