させる ⇒ さすTo make someone do something (causative)

The auxiliary verbs せる and させる will be modified in 関西弁(かんさいべん), creating a new form that interacts with the indeterminate form of verbs. In the case of う - Verbs, this is the form that interacts with ない, not the form that interacts with う. In standard Japanese, the せる and させる forms are referred to as 'causative' (someone/thing is made to perform an action). This meaning stays the same in the Kansai dialect.

The kansai form of せる will be す (with う - Verbs), while させる will become さす (with る - Verbs, する, and くる).

• 赤(あか)ちゃんにベビーフードを食(た)べさす。

  I make the baby eat baby food.
• 息子(むすこ)を一人(ひとり)で買(か)い物(もの)に行(い)かすと無駄(むだ)遣(づか)いをする。

  If you make my son go shopping alone, he spends money frivolously.
• 私(わたし)は疲(つか)れたらすぐ妻(つま)に運転(うんてん)さす。

  When I get tired, I make my wife drive.
• 迎(むか)えに来(こ)さすの？歩(ある)いた方(ほう)が早(はや)ない？

  You're going to make them pick us up? Isn't it faster to walk home?

Caution

These short forms of せる and させる are 'preferred' in the Kansai dialect, but are not a requirement. The standard forms may still occasionally be heard.