She wasn't his original target. He was supposed to put a bit of fear into a young lawyer who was bugging his boss, but when he got her by mistake... well, you just don't turn down a sweet gift like that. Sure, she could always escape and report him to the cops, but that's why he had his basement built the way he did... and after a little Stockholm syndrome he was sure she would see it his way.
Oh it'd be easy to convince her - just tell her (part of) the truth. She wasn't the target, but the team mustnt let evidence run around. He could let her escape right away of course, but the boss would send some cleaners to make sure theres no nasty evidence.
Better to lay low in a hidey hole for a few weeks until the original job is done and things have settled. Don't worry, I'll bring you food every day and make sure to fight the boredom. ;)
Oh it'd be easy to convince her - just tell her (part of) the truth. She wasn't the target, but the
