What to do when a Guy starts to hate you and then you find out he likes u?

well this guy i knw really hates me cause he keeps talking wif his friends about me ???dunn0 wat...and then the next few days my friend sayz she heard that he likes me but i thought she was talking all crap!!...but then on the bus he asked me out!!! what do i do, i say yes/no??? or jus ignor him.