I think the only way to do that would be to ask her.

I don't think I've ever been in the position to lend a large-ish sum of money. Neither of my siblings would approach me, preferring to deal with each other or my parents. Probably because I'll give them my (un-asked for) opinion as well as the cash.

Just to reiterate. The key condition in the original post is that both parties have demonstrated fiscal responsibility. I would venture that in most cases where things go sour, this condition was not met in the first place.

squished

To take the emotional aspects out of lending to friends/family, you can use CircleLending or Prosper. CircleLending charges $99 for agreement only / $199 for loan servicing. You can also use Prosper -- the person you want to lend to posts a listing and you then bid the entire amount of the loan. (If somebody else sees the loan first, likes the terms and jumps in -- great!) With Prosper, it's an extra 1% in interest to cover loan servicing. Which is cheaper depends on the amount. There's more P2P lending startups coming online (Virgin, EBay, Zopa) which may also work.

I was raised in a household that taught me fiscal responsibility by observing those around me. I've borrowed money from my parents (usually with a nominal, but below-market interest rate) and even loaned money to my big sister when she was too embarassed to ask our parents. It hasn't caused any tensions in my family and I'd like to be able to do the same for my kids someday.