Leon finds Botan a fairly pleasant and chipper person. Which surprises him a lot because he never thought he'd be talking about potential Pokemon music careers with the grim reaper but such are the variety of the people of Pokeworld. She's very cheerful and friendly but he's still uneasy to talk with her because, y'know, death. Which isn't a topic Leon likes to dwell on too much given the nature of how he died.

Other than that awkward angle he's not adverse to having a chat with her and developing a friendship as Botan herself is easy to get along with. He's especially keen to see where Aku the Gengar will go next, and he's actually thinking of contacting her about a collaboration effort between Aku and his Jigglypuff, Mari (who also wants to go into the singing business). But whatever crush he might've developed on her (because let's face it, she's pretty cute) died when he found out about the whole guide to the underworld thing.

Tl;dr, no Joe Black happening right here. But he's cool with being friends.