Looking for a specific Fantasy Book?

[danish162534]

I have read this book several times but it's been more than 2 years since i have read it. I can't for the life of me remember the title of the book but i remember the story somewhat. It's about a noble family that has come up on hard times. The main character is the ******* child of the count (or whatever rank his father had). After the counts death his brother came to live on the property as he inherits it because women can't own property and the main character is illegitimate so he can't own the property either. The main character is special because he is half human and half something else (I don't remember exactly what word the author uses but basically an elf). They live on a small manor in the country side so they can stay away from the counts brother who wants to make the mother into his mistress. They can pay the rent on the manor only through the life endangering missions the main character takes. They hear of a tourney the king is holding which will award a manor to the one who wins it. The main character hears of it and decides to participate in it so they can own the manor and thus save the money that goes in renting the one they currently reside in. He wishes to use the rent money to make a dowry for his sister. The tourney is actually for finding the right person to accompany a sister (witch or something) into a very dangerous mission to close some kind of gate or veil that seperates the demons from invading their lands and killing them all. He wins the tourney and becomes the person who will go with the sister. He first refuses the charge but then the king offers him a substantial amount of money to do this and he agrees. Near the end of the novel we discover that he is actually the half brother of the king.

I have been looking for the name of the book for so long that i am going crazy. If you have any idea what book I am talking about please tell me immediately. Thank You.