If Bellatrix thought she was hiding her displeasure at the situation, she was sorely mistaken. Of course, Voldemort doubted highly that she'd ever try to truly hide anything from him, but her efforts still hadn't gone unnoticed. He didn't comment on that, however, instead casting what might pass as a disgusted look toward Merope before his expression softened as much as it was capable of doing given his drastic, less than human features.
"The clothing first, Bella," he murmured as he peered down at his mother. He loathed her for having slept with a Muggle, loathed her for having not been strong enough to live beyond her own ridiculous pain. He loathed her for a great many things, really. Yet logically he knew, if she were to perish, he might simply cease to exist. And they couldn't have that.
"You will remain here, with me," he told her finally, once again speaking directly to the wisp of a woman. "If you require anything, do not hesitate to say so."
Then he turned, to face Bellatrix fully. A few strides and he'd crossed to her, pale fingers dancing upon her cheek in a mockery of a lover's caress. "You have done well tonight, my faithful one," he stated with what might pass as a hint of pride in his tone. "It will not go unrewarded."