"Same price for the voice-link rocks, and a few alarm-sticks to call you in for fires?" 

Wait, what if she's the sort of adventurer who'd set her own fires to be a hero extinguishing them? 

"Say, fifty gold pieces for one alarm stick now, to be refunded by you if we break it and you don't help with the firefighting. If you can help then we'll talk about buying more after."

Wait, what if none of the infusions she sells work except for the ones she offers for testing, by some trick of her strange magic?

"And leave us a few of your hairs, so if you don't show at all when we break an alarm-stick we can scry you to check whether that's because you're injured or captured by something?"

She is running on too little sleep for this. Lesser Restorations help but they're not enough.

"What, we gotta get the coin priests in on this? I'll charge extra for the annoyance. Also, letting you track me, el oh el. El-mao. No. Here, five free samples."

She waves her hand as if doing a slight of hand trick and half slaps them onto the desk, five unassuming wooden sticks.

'el oh el'? 'El-mao'? For a moment she thinks that Weiss has switched to another language, which makes her consider whether she had a translation spell that has worn off at a bad time, which is what it takes for her to finally make the connection between the mystery magic fox who turned out to be a shapeshifting foreign adventurer in service to the Queen and the fox-eared adventurer in front of her. 

Okay. Ignore the foreign slang. Reorient. 

It wouldn't make sense for her to be trying anything fraudulent if she's an agent of the crown. Cressida knows that Ileosa has little respect for the Guard, but if she were to tip into outright hostility then that would probably take the form of some grand dramatic gesture, nothing so petty as selling defective magical services for a few hundred sails.

Wait. Pettiness. Oh gods, this is a gesture of a different sort. One that says 'You can't do your jobs of maintaining order in my city, you're so pathetic that you need the charity of one of my minions who can toss out infusions like pullers⁷ to be able to fulfil your most basic responsibilities.' It's an insult with the fig-leaf of a transaction to avoid making a complete joke of the Guard, a fig-leaf that Ileosa can remove at her leisure whenever she feels like twisting the knife. 

The worst part is, those infusions really would be a godsend now that she can trust them to function. She doesn't have a choice. She's going to have to swallow her pride and accept the insult and assistance alike. 

Maybe if she can bring the streets under control again, the Guard's relationship with the crown could return to a cordial distance? But no. In her heart, Cressida knows this is just the first insult of many from her new queen. 

⁷ Pullers: Tiny, chewy sweets made of sugar, honey, and 
maple syrup held together with caramel and wheat 
flour. 

Little Cheliax is not a high-trust society.

It is what it is. Her pride is less important than keeping order, maintaining the law, giving the people of the city a hope for their afterlives.

It's also cutting that Weiss doesn't seem to realize the queen is using her to deliver this insult. The adventurer before her is probably Chaotic Good, sent here by an artful offhand comment of Ileosa's. Biting back at her would just be killing the messenger.

Cressida sighs deeply. Her shoulders slump, and she leans down to open up a drawer of the desk and take out the coinage needed.

"One hundred gold pieces for the fifty castings of Darkness, fifty of the speaking-stones, and with your five alarm sticks thrown in for free? The Guard is very grateful for your generosity."

"Sure, why not." Headshake. "The talk stones... Might go out sooner if you use them a lot, if I'm putting one darkness's worth of magic in. And it'd be better if I had actual rocks. You can wait until they definitely do work to pay up, even, it's not like I gotta make rent." 

She can just go to the Between. It's always summer there. She pushes away the urge to defend herself to the cop. It won't help it never does.

"And I still need conditions to activate the darkness. Could do a command word, a physcial condition like a button to press or a ribbon to pull, or breaking them- Breaking is what I usually do for emergency alarms, but being jumped and also suddenly darkness might be bad."

Frigging cops, always wanting to get fingers in to track and control. But she can put up with the dread and do harm reduction.