difference between lucky and fortunate

lucky - adjective(азтай, хийморьтой)I would say I was lucky to win the lottery, but not likely I was fortunate to win the lottery.
luckier, luckiest
having good luck
      ---- She was lucky enough to be chosen for the team.
      ---- His friend was killed and he knows he is lucky to be alive.
fortunate - adjective(хувьтай, золтой) is used in a more 'serious' sense when talking of more important benefits as in:
having or bringing an advantage, an opportunity, a piece of good luck, etc.
       ---- I have been fortunate enough to visit many parts of the world as a lecturer
       ---- I was fortunate in having a good teacher.

difference between fortunate and lucky

• I think answer to you question could be - You are lucky, that you met a really nice girl.
  You are fortunate if she loves you and you will be together
  
  I found a pretty good explanation - I hope it will help you:
  
  
  'Lucky' suggests that something good or beneficial has happened as in: You were lucky you chose that horse in the race because it came in first. It was lucky that I took my umbrella because it started to rain as soon as I left the house. 'Fortunate' has very much the same idea but is used in a more 'serious' sense when talking of more important benefits as in: It was fortunate that his parents had enough money to help him start his business. She regards herself as a fortunate woman becauase her children have been able to support her during her presenr crisis.

• I don't think they are interchangeable in those situations. I would say I was lucky to win the lottery, but not likely I was fortunate to win the lottery. One would say, I was fortunate to have such a wonderful husband, but not likely I was lucky to have such a wonderful husband. 'Luck' seems related to pure chance, whereas fortune seems more like a blessing, i.e. a divine power has a finger in the pie.
  
  I would not say I was fortunate that the car didn't kill me, but instead It was fortunate that the car didn't kill me. With 'fortunate', it seems there's an implied 'because': It was fortunate that the car didn't kill me [because] I wasn't ready to die right there and then. With 'lucky', there seems to be no such implication, there's just a focus on the situation at hand: I was lucky [in that] the car didn't kill me.