Do you think my fiancee will understand if I don't buy her an expensive wedding ring?
Oh, I don't know, the wedding ring is really important. Why don't you want to buy an expensive ring?
They cost so much money and we could put that money towards a home instead. I really can't afford to spend much.
Not everyone has a lot of spare income on hand to throw at a wedding ring. If you don't have the ability to spend a lot of money on a ring that's perfectly fine. You should think about trying to find a ring that has meaning or a symbol that is important emotionally.
I hope she'll happy with the ring that I get for her.
Talk to her before you start shopping for rings and tell her how you feel about the expense of the ring. The two of you can decide together how much should be spent on the ring and what would make you both happy.