Leonard's smirk may have originally have annoyed Sara, but his voice was much like his eyes. It fascinated her. Never had she heard someone speak like that. It wasn't an accent really, just a unique drawl to his speech that made her want to hear more. Sometimes he emphasized words not usually accentuated, but it always sounded right for how he spoke. It was almost a different language, but one that Sara was suddenly eager to learn. She'd let him read the phonebook to her if he read it in that voice.
His brand of sarcasm wasn't for everyone, but from the moment they had a good conversation, she knew he'd always keep her entertained. Especially when it was used on those who didn't always get it. No one could ever accuse him of pulling punches, but even brutal honestly was a good quality, right?
No matter what, though, his voice always added to his expression. If he was pleased, there was a light to his voice. If he was angry, it was almost a growl. If he was bored or annoyed, there was no mistaking that. His voice dripped with irritation. But his snarkiness was part of the appeal. The man was brilliant and wasn't interested in dealing with those who couldn't keep up.
As time went on, Leonard's voice would sound different to Sara, and only Sara. She had heard his whispers before, very often a mission required it. But the whispers meant only for her ears, those sent shivers down her spine. Sometimes it barely mattered what he said, but just how he said it. (And damn, if he said it in another language…) The teasing banter which inevitably turned into flirting (usually of the most lecherous kinds), while making the rest of the crew uncomfortable, always made her feel like he could actually keep pace with her. Most men (and women) could barely do that, but she had an unexplainable confidence in Snart- if he could put his money where his mouth was.
Eventually, she learned that yes, yes he could. His tones in the bedroom (or wherever the mood struck them) were enough to get her ready. She swore his voice dropped an entire octave when he would tell her what he wanted to do to her, or appreciated what they were doing at the moment. She'd never had such a vocal lover, but it didn't surprise her. She wasn't sure Leonard could turn his mouth off. But most of the time, that mouth benefitted her, so she didn't complain.
His voice shook with emotion as they recited their vows, which surprised her a bit, but made her love him all the more. And the sweet lilt he gets as he speaks to their baby, fills her with warmth.
As he turns to her with that smirk, and that look in his eyes, and that voice telling her exactly what he has planned for them, she's reminded, once again, how much she loves this man.