I can make it worthwhile to help with this," you say. "What do you like? Skiing? Yachting? Opera? Scuba diving lessons, improv classes?"
The woman blinks.
"Or cash," you say. "We can also do cash money. Though in that case, you might have to declare it for tax purposes."
"Um," says the woman. "I guess, uh, I'd like to take my sister to Baja."