How to reply to "not looking for a relationship" in cold approach/text

Hello again PFW community,
Many of the girls I come across who don't have boyfriends give me a variation of that line to decline. Obviously part of it is from my own inexperience with building comfort and attraction (which I'm working on), but what could I consider using in that situation to make it less than 0% possible?
Also, what sorts of things would you recommend to try before suggesting a date/asking her number which could reduce the chances she'd say something like that, e.g. giving her room to chase?