Despite Sakura's initial reaction, Steph is pretty impressed at how she's handling her fear, especially with how she wants to make sure the 'monsters' don't hurt anyone else.

"They're called cars, and they're not monsters," Her smile stays gentle and reassuring, and there's no indication that she's not telling the truth, "They're made by people. We sit inside them and use them to get around. They go pretty fast, but they're supposed to stay on the road, so if you're careful about staying on the sidewalk they won't hurt you."

She's not entirely sure if that explanation will make complete sense (she's never had to explain a car before) so she's watching Sakura carefully to see if she gets it, and to see if Steph will need to elaborate a bit more.