Why the same reason you asked that question. Curiosity.

[ This being a very straightforward sort of question and not one he felt the need to hedge around he answered truthfully... but leaving out those bits about being a fugitive from the law evading, temporarily, a sentence to be carried out on him by his own people. No need to muddy the waters too much was there? He was curious and that was the main reason he had decided to go on this mission. ]

I want to know what Fortuna is, if indeed it is a real place. I do love an adventure, don't you?

Why did you decide to accept?