you will discern it by the time you got a lot of time being with that 'someone'. your heart will tell you about your true feelings, and you just cant fake it. :)

將心比心 - True

I'm not quite sure, but perhaps you mean: How do you evaluate, if someone does really have strong feelings about you? If so I can give an advise: Just go with your instincts. That what your gut response is telling you is mostly correct.

Hello Jan I don't think it is the right thing to do here, cause if you start with false feelings and then true feelings your friend will be lost very quickly... and after a while your friend will be very disapointed... Another thing for me is to avoid to judge anyone...