you dont, its on their site.

If you cannot find the requested donation on the providers web site or ad on Eros or another escort mall you do have to find out prior to the appointed meeting. Often times the donation listed in TER reviews is incorrect or dated, (yes there is inflation and sometimes there are specials too) so it can only be used as a guide.  

It is always best to keep it polite and discreet.  Perhaps asking in a variation of the following:  "I'm really looking forward to meeting you, and I know it’s distasteful to discuss this, but, what is expected of me if I want to meet with you for 2 hours."  If she doesn't understand you then say:  "I'm sorry but I can’ find where the required donation is listed on your site, could you direct me to where I might find that out?

If none of these discrete suggestions work either she is a natural blonde or better yet find another provider who understands how to communicate properly.

your gift amount is _____?

Whenever I call a provider or a massage parlor I ask for their hourly rate for the massage. If you are dealing with an establizhed provider, that is all you need to know and just pay up front in a visible location and go with the flow. Providers  know why you are paying them for their time. Just show appreciation and respect and you are most certain insured a great time spent.