The boy who helps solve a prince's murder or something along those lines. The boy had tarot cards in the first chapter, draws the Death card, and says how it's about new beginnings? I'm sorry, that's all I remember from back when I was ten.
1 Answer
Midnight Magic, by Avi
The book opens with Fabrizio, the Magician's servant / apprentice, drawing the "Death" tarot card:
In 1491, in the Kingdom of Pergamontio, there lived a twelve-year-old boy by the name of Fabrizio. He was the sole servant of Mangus the Magician.
[...]
Eyes shut, praying to see Riches, Fabrizio turned over the ninth and final card. When he opened his eyes and saw that the card was
DEATH
he gasped.
Midnight Magic, chapter 1
The Magician and Fabrizio are summoned to the castle to deal with a troublesome ghost, who is then revealed to apparently be the ghost of the Prince:
When Princess Teresina hesitated, Fabrizio leaned forward to hear her answer.
Finally, the girl said, "I know it."
Mangus: "Do you think you know whose ghost this is?"
Princess Teresina: "My brother's."
"Brother!" Scarazoni cried with such vehemence, Fabrizio started. "You never said so before, Princess."
Midnight Magic, chapter 12
Identified by recognizing the description in the question.