She's a model employee. She gets to the office every morning at 7:45 am, two hours before he strolls in, hands shoved into the pockets of his Hugo Boss suit, shouting her name (he has only two settings: loud and ear-splitting; she's learned to tune him out when she needs to). She drinks her coffee, eats an orange, and sorts through his email and her own while she listens to the morning news on the radio. She doesn't call him Mr. Sionis in her head, or when they're in private. She doesn't call him anything but sir, or boss, when necessary. She knows he hears the amusement in it, but he either doesn't care or he's simply biding his time until he no longer needs her.
She's not a fool. She didn't just happen to end up working for a mob boss, horrified when some do-gooder told her the truth. She arrived in Gotham with the drive to succeed and the knowledge to take over the town, but she'd lacked connections, and he gives her those. She knows as much about the business as he does (more, to be honest)--enough to keep her safe or get her killed--but he's the only one who knows that. The newbies think he's in love with her and the veterans think she's in love with him. She doesn't know what the capes or crazies think, and she doesn't care.
She's not in love with him, and if he's in love with her, she hopes to god she never finds out. She works for him because he respects her, as much as he respects anything (she's in the top five with money and guns and the power of fear), because he takes her seriously when she talks about supply lines and distribution centers and the way even minor fluctuations in the overseas exchanges affects their business, because the way she collates information works with the way he processes it. Because she's never been afraid of him or what he does, even though she knows she should be.
There are things he doesn't know about her--Li isn't even her real name--and she prefers it that way. Half of the very generous salary he pays her gets routed through several anonymous accounts and finds its way into the hands of her mother, who thinks it's an annuity from the life insurance policy on her daughter, who died in a fire. She doesn't miss her mother (much), but she also doesn't want her caught in the crossfire when bullets start flying, and they start flying all too often in this business.
She knows, and she knows he knows, that if they both survive long enough, there will come a day when he'll have to take her out, or she'll be the one sitting in the big leather chair in the corner office.
But that day hasn't come yet, and she has email to answer.