Advice on talking to strange men in the Red Light District

Last night while I was walking home around dinner time, some man on a bike stopped and started talking to me. I was tired and hungry, and my first thought was 'Really? Do we really have to have this conversation now?' Because even if it's been awhile since I've been randomly stopped on the street by a strange man, the conversations tend to proceed in a similar way.

The following is a rough idea of yesterday's conversation.
him: Hi. How are you?
me: Fine.
Can I ask you a question?
Sure.
What's your name, by the way?
Brenda
oh, let me introduce myself: I'm David. What was your name again?
Brenda. 
I'm from Amsterdam. Where are you from?
Amsterdam.
I've been here for six years. How about you?
seven years.
I'm from Ghana, by the way.
I'm from Canada.
oh, but you speak very good Dutch.
Thanks. I live with Dutch people. And I married a Dutch man.
And you're still with him?
Yes.
Okay. bye.

I don't really understand these conversations. And yesterday's conversation even less. I was more unfriendly than usual (sometimes I do smile at others - simply because I like seeing people smile back), and my clothing (blue jeans, old coat, glasses, sport shoes) indicated fairly clearly that I was not interested in attracting any male attention.

What I do know about these conversations is that the sooner I can mention I am happily married, the sooner the conversation will be over. I guess I could also just say at the beginning that I'm not interested, which I did sometimes do, but that seems less gracious. Besides, I kind of like the challenge of showing that one can be friendly without wanting something out of it.

Before I was married, the conversations could get a bit long, probably because the men didn't know how to respond to my offer to come in and have coffee. They had obviously shown interest in me and seemed like they wanted to know me better. Yet, they weren't expecting that kind of hospitality, and surely not having to come have coffee with me in the common room (shared by the 50 or so people I live with). So, the conversation would drag on while the poor man tried to understand what kind of hospitality I was actually offering and then try to come up with a reason why he suddenly had to leave....