I have always loved her but she doesn't want to marry me. We will get married in two days. I can't wait to marry her.
Are you positive you are sensing that she doesn't want to marry you?
Yes, I don't know what's wrong with her. She can't find a better guy than me.
Marriage is a partnership and requires both people to feel the same about each other in order for it to be successful. It's wrong to force someone who doesn't want to marry you into marriage as it will cause a lot of mental anguish and resentment for that person. You should not marry that person who isn't into you and instead find someone more compatible or otherwise you will risk getting divorced later.
You know that she has a really low self esteem. I think she just wants to settle.
It doesn't sound like it will work out unfortunately. You still have time to stop the wedding. Make sure you know her true feelings about marriage and if you do love her, you won't force her to go through with the ceremony.