It helps, honestly. It helps that she's calm and that her tone is light - it helps that the second death-related entity he's met is chill, or is at least acting like it. (To be fair, he probably could handle two high-strung Deaths on the same train, but that doesn't mean it would be fun for anybody involved.)

(...gods, has Thanatos met her yet?)

He tries for a smile and still doesn't quite get there, but it's close. "Because trains don't exist where you're from, or because people don't usually welcome you?"