That's what I have heard from people who understand this more than I do. Do you really think we can understand everything. I mean there is always so much to learn.
I have also hear that two people could be reincarnated because they never settled something in their past life. And somehow they meet again and deal with the same issues throughout their current life.

I do believe in reincarnation. I believe that there are many things that cannot be explained any other way.

As to the reasons for being reincarnated...I have no idea. Sometimes I do think that it is to learn. Sometimes I think that it is beyond  our understanding at this point.