Sarah let out a snort of laughter as Toby confessed he was adopted- not because it was funny to be adopted, but because clearly her outburst was so ridiculous that Toby had felt the need to reciprocate, and it was adorable and wonderful all at once.
"Sorry. You being adopted isn't funny, I promise. It's cool, actually. I've never met anyone who's adopted. I'm just laughing at myself for being... ridiculous and apparently incapable of making a good first impression." And digging herself a hole quite steadily, it seemed.