If it is a first time, and you are picking her up in your car, then in the car would be OK.

If she is meeting you at the restaurant, there may be a quiet place where you can discreetly place the envelope in her hand or slip it into her coat pocket, but be sure you are not seen doing so.

Otherwise, after you leave the restaurant would be a fine time and place to make the hand off.

you don't do it in public thats for sure..Maybe a rose with a CARD  you could put the donation right in the card and no one would know as you whisper it in her ear as you lightly kiss her cheek..
A scene in a movie huh?  
But it will work that way
Jay

As it's the first meeting, the lady is unlikely to want to spend an hour or two with you without first being paid.  

Is it possible to meet up first in your hotel or home and deal with the donation then?  

If not then the above suggestion about a rose and a card is fantastic (just make sure she knows it’s her donation and doesn’t open it in public!)

I prefer that I receive my donation as soon as possible, so I don't have to concern myself with it the rest of the evening. For the love of all that is good and holy, please don't make me ask for it. On my dinner dates, I try to meet the gentleman in his room (or at his home) first so we can conduct the "business" aspect there. That's not always possible though, and some ladies prefer to meet in public first.

When giving her the donation in public, it will need to be discreet. Bury it in a gift bag or place it in a gift box (personally, I prefer not receiving a greeting card bulging with cash). What, is the maitre d' going to storm up to the table and accuse you of patronizing a prostitute? Hell no! He'll assume she's your wife or fiancee or new girlfriend you're trying to impress, or just a hot young thing you were lucky enough to take to dinner.

Just use your common sense, and follow her lead....

I've only been on one dinner date (BTW - with one of the ladies who have posted in this thread ).

Have the correct amount on you at all times, IN AN DISCRETE ENVELOPE.  When I say on you, I mean in an inside jacket pocket, a trouser back pocket, etc.  Keeping it in your shirt pocket may be a bit obvious, and you definitely don't want to open your briefcase.  Just let her know that you have it accessible, and let her suggest the time to transfer.

Re: Dinner Dates

My friends always bring a present with them and the donation is usually in a form of a gift card or in a box of champagne. Its very discreet with an added touch.

- A.L.