Quote Originally Posted by Eric C. View Post
I think it can perfectly be said "мне жаль книгу" and "мне жаль книги" as well. The same with "мне жаль этот дом"/"мне жаль этого дома", etc. So, my guess is you can't figure out what case is used for "тебя" in the example you gave.
Please check the It-ogo's post carefully. Different cases are used for different sense. I hardly can imagine any context where "мне жаль тебя" would imply "тебя" in genitive case. Since "мне жаль тебя" is "I feel sorry for you", "тебя" is in accusative case here.