By luck, Vaan didn't mean he made a mistake in flirting with Lady Solana. Vaan knew Lady Solana was a Senior Witch thanks to his Magic Vision.
Furthermore, Vaan was adept at reading people's expressions and subtle body movements, allowing him to understand when a person is open or closed to more intimate interactions.
And from their short interaction, Vaan had learned that Lady Solana was open to flirting but closed to everything else beyond that.
Nevertheless, Vaan didn't always need to flirt with the intention of bedding a woman.
Vaan could also flirt to improve his impression and approachability, thereby building a closer relationship and engaging in topics that wouldn't be privy to strangers normally.
In other words, collect information.
Of course, the prerequisite is knowing when a person is open to flirting or not. Otherwise, it will have the opposite effect.
Lady Solana was someone who sashays her plump rear when she walked.
