A peasant becomes soldier and decides to go to war in Sahara and fights alone because a man of authority snatches his first love. Rejected by death, a ghost suddenly appears to him, just to advise him to leave his place to find another love. When meets her ,both decide to get married but confronted by fierce and unpitiful rapist .

Still too long-winded — for a logline you need to squeeze the essence of the story into ONE sentence if possible — two at most:

“A broken-hearted peasant with a death-wish joins an army in the Sahara, only to be confronted by a ghost that tells him he must save his one true love from a violent rapist.”

…but this is still too long, and possibly not an accurate description of your story — but I hope it helps.

Good luck.