after failing three huge missions an assassin is given a opportunity to get to the top by killing the most dangerous and powerful drug lord/Mafia in the country… but his past come to aunt him when he finds out its his oldest daughter

When the new young hot head is enthroned head of a mafia family, an aging hit man is ordered to prove his loyalty and competence by killing a witness: his own estranged daughter.

The emotional complications would amp up the script, but that is too much detail to cram into a logline. (And if the boss gives him the job to prove his loyalty, then it follows that the boss questions his loyalty as much or more than his competence.)

what if the daughter is not only a drug lord but also a loving mother and wife that the dad didn't know about because they stopped talking but as he now sees her in a new light he then starts developing emotions for her but also need his job and need to prove that hes loyal to the boss and what if the boss knew that it was his daughter and purposely gave him that job JUST so that he would see how loyal he was

what if we made the daughter not only a drug lord but a loving mother who has a family that he never knew about .... thus making the decision harder for him to kill her and to prove his loyalty to the boss

I like your point on her beign a good person

I believe upping the stakes is better.

Why not make the daughter sympathetic. Instead of a drug lord, why not make the daughter a witness against the assassin's boss.

Not only does he have to kill her to prove his loyalty, she's an innocent who was just at the wrong place at the wrong time.

If she's a drug lord the audience is 'eh' because she is a bad person but if she's a good person the audience will be on her side and will make the story more interesting.

I agree with Jim Corona on the first point. There is no margin for error or mercy in business of assassination: three strikes and you're already dead which is why I changed it to one bungled job.

But I disagree on the 2nd. I think more films need to be made -- can be made -- with strong female characters, heroes and villains. (IMHO, part of the problem with a dearth of strong female characters is a shortage of female screenwriters who aren't clueless as to how to portray woman as women -- strong women -- instead of portraying women acting like men in drag.)

Could perhaps the hit be on his estranged wife, who he still loves. They have a daughter together which adds to the dilema as he could be fearful she'll grow up to be like him. Based on Jim Corona's questions, i to have to ask why they would they would entrust this task to a failure.

Two thoughts:
First, go with dpg's basic concept, minus "professional." I think it's safe to assume the assassin is a professional. The idea of atoning for a single bungled assignment is much more believable than three failed attempts; mobsters wouldn't permit three blown attempts.
Second, I love the idea of the hit being a loved one, but I don't think a daughter who is the most powerful drug lord would fly. If it's his daughter, our society would assume she's a first-class bitch, and thus deserving of the hit, which makes it too easy a choice for your protagonist, and if she's the most powerful, she's REALLY deserving of the hit. Making the hit his son, though, offers a much deeper (and "acceptable") quandry ... and your protagonist could have VERY mixed feelings about the hit. Going further -- if you make the hit a lower-level drug dealer, the choice would become increasingly difficult. Finally, what if the protagonist is the hit's MOTHER?
Good luck!

After bungling an assignment, a professional assassin is given one chance to save his life: he must kill the most powerful drug lord in the country -- his daughter.

so could you give me any suggestions on how to end it because that's the part im struggling with

I would consider leaving out the fact that she's his daughter from the logline.