Can best friends be the best life partners?

Yes. If bestfriends become life partners they are better off being husband and wife because they have no secrets in between. Bestfriends shared almost everything problems, excitement, fun, etc...

I married my best friend. We were friends for three years before we began dating. We learned all about each other through our friendship. We watched each other grow from our disappointments in relationships and life. We were able to see what makes each other tick by not involving the intimate pressures of being a couple first. I am so thankful we were such good friends before we became lovers. I often give my single friends the advice to meet a person, take it slow and get to know each other as people before you take the big plunge. I know it is case by case and every person is different. This is what has worked very well for me though!

I don't think so. It is a case to case basis. As on my part, me and my best friend tried it. We risk the friendship by turning it into a romantic relationship. But we failed. What's worst is that, we even lose the friendship.

...yes, i believe best friend can be best life partner, i wouldn't have my wife if i wouldn't believe...injustice? for what?

It seems that there are no inevitable cause-and-effect relationship between friends and life partners. For some people, they may keep a good relationship with their best friends but they never fall in love with each other. You see, friends and life partners play different roles in one's life; friendship and love are different things completely for our whole life. Of course, best friends can be the best life partners. But I haven't met such a situation before.