How can I ascertain whether my product will be bought by the target market, rather than just something they want?

 I am doing market research (inc. competitor analysis, online questionnaire, reading professional surveys), and am trying to get as near as possible to the answer before doing prototypes.  I appreciate that once I have prototypes I can start getting objective reviews and then selling.  However would like to do as much as possible before prototyping.  Ideas gladly received.  Thanks

Asked by Helen Williams | 5 Years ago in subject: Ideas , Starting up guides , Starting-up and in industry: Online , Shop / Store , Retail and Leisure , Art / Creative