Some 20 minutes before the finale to the Timber Lake Playhouse's Dirty Rotten Scoundrels, you'll finally hear something that you hadn't heard once during the musical's first two hours: a legitimately sincere number. Granted, this romantic ballad is being sung by a practiced con man, and the object of his affection is a young woman from whom he's trying to swindle 50 grand, and he's only been hitting on her to prevent his rival from scoring first. But, hey, sincerity is sincerity, and besides, it's the only heartfelt moment you're gonna get.