When a yound man falls in-love with a beautiful woman, he fights for his life, when her jealous fiancee determines to kill him.

This logline attempt suffers from multiple problems. So first of all I suggest you look over the Formula tab at the top of the page.
Now onto the problems.

The logline has no sense of coherence, and seems to be chronologically jumbled. It is also vague. Reading how it is now, how does a young man falling in love lead to him having to fight for his life? Shouldn’t the jealous fianc? (a male who is engaged is described as a fianc? with one ‘?’, while female has one accented ‘e’ and one without.) want to kill him before he has to fight for his life?
What is the main character’s goal? What does he wish to accomplish? What conflict will be resolved by the end of the climax? What specific event causes the character to pursue this goal? What is the antagonist’s goal? Why is he pursuing that goal?
How does “fights for his life” translate into a specific, achievable goal? Also, the logline mentions nothing to suggest the woman falls in love with the main character or anything to give the antagonist reason to want to kill the main character.

But all of that aside, the single most important thing for a concept is it’s hook. The thing that will make a producer want to read your script. Your logline suggests nothing new, unique, something to set it apart from countless other dramas about two men fighting over a woman.

I hope this helps.