How can I reconcile my desire to marry a specific person, despite the objection of my parents who wish for me to marry a relative?

The parents do not have the right to force their daughter to marry someone she does not desire, even if the young man is of good character and handsome. What is important is his religiosity. If you desire him, inquire about him from trustworthy individuals. If they praise him, then there is no harm in you offering yourself to him through someone you trust. If there is mutual agreement, perform Istikhara (prayer for guidance) to Allah. It is recommended, along with Istikhara, to seek forgiveness (Istighfar) and give charity (Sadaqah).