They all but can't be trusted in public as is, much as Bellatrix likes to turn a blind eye on her own actions – at least that moment had been one of self-awareness. She considers them... close friends. The rest of the world considers her very much engaged. So some behaviours just won't do, especially not considering the considerable list of benefits between the two of them. And even if things hadn't, uh, escalated during any potential fights at the bookshop, it would certainly be bad press nonetheless. "Attentive one, isn't she."

So much for Marlene. She thanks him for the coffee, and, knowing full-well that the spell needs a bit of an extra poke to really fulfil her sugar-needs, doesn't even remark on the fact that he refined it muggle-style. Anyway, after a sip of it, she casts a quick spell over the manuscript: a general repellant, because she feels no need to stain his property, but she is even less inclined to put away that supernaturally delicious croissant.

"Oh, but do we ever like a challenge. I reckon we may be quite through with this before late, don't you?"