Why? You ask that? You who killed your mother to come into the world?
And if you serve faithfully, you will be rewarded with a suitable wife - and I would let myself be consumed by maggots before mocking the family name and making you heir to Casterly Rock!
And when the time is right, you will be given a position fit for your talents, so that you can serve your family and protect our legacy. We'll find you accommodations more suited to your name and as a reward for your accomplishments during the Battle of Blackwater Bay. The day Jaime put on the white cloak, he gave up his claim to Casterly Rock. Jaime is your eldest son, heir to your lands and titles, but he is a Kingsguard, forbidden from marriage or inheritance.