This article from Daily Mail goes into detail, but these are the questions you should ask your partner before marrying them to get to know them better.
1. What helps you to relax?
2. What makes you feel loved?
3. What is our financial situation?
4. What have been your biggest traumas?
5. Where do you draw the line between secrecy and privacy?
6. How do you deal with conflict?
7. What role should extended family play in our relationship?
8. What are our deal breakers?
9. How are we going to stay connected while maintaining independence?
10. How will we divide domestic labor?
11. What's something about me that concerns you?
12. What is our shared vision?
I think a good amount of those questions are probably answered through shared experiences and conflicts with your partner over the course of your relationship. But if you don't know the answer to some of those questions, maybe you should consider asking your partner for clarification.
I also think these are great things to ask your partner even if you don't plan on marrying them.
Get the full article here.