Aagha, I have a question regarding istikhara. What if a person seek istikhara for some very serious matter on which he is unable to decide and the istikhara has come against the desire of a person and if doesn't follow on the istikhara. please advise.

See there are the stages first use your wisdom if one is confused or unsure then seek advice from experts people and if still confused then do Istekhara but if you consulted then follow the Istekhara inshallah you will get better than this one.