Scar took 'wouldn't be averse' as Lust's safe way of saying yes. He was learning, little at a time, how to read her.

He brushed his fingers against her cheek, gently urging her to turn her head close enough to kiss his. He was a little better at this than he had been the first couple of times. It helped that they never did more than light, nonsuggestive sort of kissing. This was easy, and it was nice. The feel of her, her closeness and her smell. Physical things Scar was so starved of.