That's where things might be slightly complicated. Getting to him is easy, considering everyone in town is probably talking, in some sense or another, about this crazy fight in town last night. The tree was set alight and a hole was made in the Inn.
Getting him out of the jail is the issue, Breaking him out is a possibility, also perhaps gaining the favor of the count or something along those lines. There's also Serge who I put in the story in order to get Sarel out of the jail in Sharee falls through.
But perhaps you just meant how does Sharee litterally get Sarel to come with her. Well, he is a man of honor, and adventure. I'd have to see what she says before I tell you if he'd join or not. Sarel isn't completely interested in money, so that won't be a primary incentive.
Tell me if you have any questions. Or message me.