Father opposing marriage with partner

For any relationship to work, both partners have to be equally willingly invested to make it work.

In collectivist societies, families still continue to have a huge say in almost every major and minor aspect of our life and somehow many of us come to believe that we owe our lives to them for what they have done for us. Unfortunately when families disagree for their child’s choice of marriage, be it due to it being a love marriage or financial status and security or caste or religion or family background, it becomes quite a difficult task for the lovers to convince them, leaving the couple to either part ways or to part ways with the families.

If your partner wants to try to work this out despite knowing your parent’s opposition, you both could try to find out the reasons for opposition and then try to see how you both could address it.
Understand your father's concerns and then try and cater to them, one at a time.
If even after all talks and convincing, despite your best efforts if your father is not ready to budge, there is only so much you can do. This leaves you with either parting ways with her or for you to be ready to part ways with your family.

This could be a difficult time for you to go through and if you find this difficult to cope with, you could reach out for counselling or therapy that could help you manage yourself and your emotions effectively through this difficult time.