You would think there would be a way using DirectCast, TryCast, CType etc but all of them seem to choke on it e.g.:
CType(\"Yes\", Boolean)
If you think about it, "yes" cannot be converted to bool because it is a language and context specific string.
"Yes" is not synonymous with true (especially when your wife says it...!). For things like that you need to convert it yourself; "yes" means "true", "mmmm yeeessss" means "half true, half false, maybe", etc.