I am now 98% certain I have found a half-brother that I have never met.
I am now 85% certain I want to contact him.
But... it's so hard to know what to say.
Dear X - Hi, This may come as a surprise but I think I'm your half-sister
Dear X - Hi,  My father's name was YY - I believe your father's name was also YY
Dear X - Hi,  My mother told me I had a half-brother and I 
think I'm certain it may be you.
Dear X - Hi, My father talked about you all the time and never forgot you (a complete lie!!).  He was a wonderful man (Hmm) and would have married your mother if my mother had let him have a divorce (probably true).
So, what do you say?  What if I write to him and he doesn't reply?  What if I write to him and he does reply?  What if he wants to meet me?  What if he doesn't want to meet me?  What happens if I meet him and don't  like him (it wouldn't be the first person in my family I don't like).  Do I put this on the back-burner and think about it for another few years?
How do you deal with this?  Has anyone done this and what were the results? 
 
  
 
Rishile