Listen and understand their point of view
The first step is to listen and understand the parent's point of view. They may be seeing something you can't, and it's important to listen to their opinion to understand why they don't approve of your partner.

Explain your point of view
When you have listened to the parents' point of view, explain your point of view. Tell them what attracts you to your partner and why you feel like you're together. Try to explain why your feelings for him/her are so strong.

Try to find a compromise
Try to find a compromise. For example, you can ask your parents to get to know your partner so they can better understand him/her. Or you can invite them to spend time together so they can see how good you are together.

Don't pressure your parents
Don't pressure your parents. If they are not ready to accept your partner, putting pressure on them will not help. Instead, give them some time to think and try talking to them again after a while.

Try not to be offended
Try not to be offended if your parents don't approve of your partner. This does not mean that they do not like you or do not want to see you happy. They just have their own reasons and opinions.

Trust your feelings
Finally, trust your feelings. If you feel like your partner is someone you want to spend the rest of your life with, trust that feeling. Ultimately, you have to live your life