I committed a mistake

I have hurt someone badly with my actions and with my thoughts!!

I have committed a mistake which is a SIN; really confused  how should I apologies?

Should I bend on my knees for forgiveness ? Or should I give away my life for to gain his trust back !!

I know that he is hurt and that too because of me !! But is it my mistake; that my mind had rewind for somewhile and could think of nothing but that very thing!!

Don’t even know how to apologies ? How do I ask for forgiveness !!!

I just hope that one day he will forgive me for the mistake that I committed..!!!!