This is one of those times that the truth comes in layers - there's a bit of fact, a bit of rumor, a bit of humor, and a bit of perspective, but you have to combine it all to feel like you actually have a grasp on it.
Rowena is widely known as a shrewd and ruthless businesswoman. She has a mind for appraising value and cost-benefit analyses, for balancing books and where to put her investments - when to buy, when to sell, what to trade, what styles are coming into and going out of vogue.
She tends to be very talented at preventing herself from suffering any meaningful losses, but also talented at noticing who does not share in this talent. Her contracts are binding, rigid, and unforgiving; she's not going to cheat you, but she's not going to stop you from cheating yourself, and she'll make sure she gets everything she's owed.
Naturally, then, she's also widely known as a thrice-damned harpy. It's not wise to bet against the House, and to go into business with her is a huge risk if there's any chance you might not have a good grip on your affairs.
That said, if you watch her closely, this reputation is her armor - and she deliberately polishes it, encouraging her actions to be framed in the most cold, calculating, and shrewd way possible. If ever she's seen as weak or charitable, it might be the end of her business empire.
Example:
The girls who work for Rowena all have terrible pasts and terrible debts. She buys off this debt, gives them a new name which ends in "na", and forbids them to reclaim their true name until their debts are paid. She encourages people to see this as indentured servitude - that she's capitalizing on collecting people who have no choice but to be loyal. Or is she just collecting the vulnerable and teaching them to seize power like her own? Skills in numbers, wisdom in deals, aptitude for appraising people and judicious thinking? Using aliases to prevent people from finding them in the meantime?
Even when it comes to girls like Khloe and Zhloe, they work hard for scraps and Rowena seems to let it happen, but do you really think it's fate that the realm's most sentimental sucker, the Warrior of Light, keeps stumbling over them in her safe havens and helping them build their dreams? Or are her girls following orders to ensure these most auspicious of meetings?
I'm pretty sure she's even torturing poor Gerolt with his debt cycle just to keep him close and predictable until he reclaims his sense of self-worth and responsibility, lol.
But, yes, the Warrior of Light often ends up on the more taxing and laborious side of any dealing with Rowena, and has no qualms about buying into and helping spread the thrice-damned harpy point of view.