[Vincent Chase]

I usually tell them I'm not looking for anything serious initially <insert excuse here>. It sets your boundaries clear and it is up to her to prove herself that she's worth something to you. Very few girls will say no to it, because if they do it appears they want to invest more than you and in terms of investment and care it is always a race to the bottom in terms of power, so yes she'll agree "I'm not looking for anything serious either" and will make up her own excuse that her boyfriend recently left her or she's been travelling the last year. All bollocks of course. Then you set the date, and the expectation is clear.

The other option is not to say nothing but make it clear by your actions, this can typically work better in social circle game, rather than online where you don't have the opportunity for such interactions until the actual date and want to screen out the time wasters.

I wouldn't use the word exclusivity but use the above. If you want to take it one take further use marriage game or appear somewhat taken going for holidays with a "friend", the more taken you are or appear to be the more appealing you become.