When a man?s marriage proposal is curiously rejected, he secretly hires a private investigator to investigate; but when the PI ends up following the wrong girl, the man must learn to differentiate fact from fiction to get to the truth.

I remember this logline as posted a while back, not sure if this is exactly the same but seems very similar to the previous version.

Here are a few problems with the elements in the logline:

– There is no clear goal described in the logline. If this is a love story, then him wanting to save their relationship needs to be specified in the logline.

– “…marriage proposal is curiously rejected…” – What does this look like? In other words, what makes her saying ‘no’ curious and how is this cinematic?
For example, after many seasons of storytelling in Sex and the City, Mr. Big finally proposed to Carrie. The proposal was a big deal (pun intended…) for her on account of the journey she went through before receiving it. If she would have said ‘no’ it would have been ‘curious’ because of the huge amount of story the audiences waded through to get to it. However, in your concept, you’re suggesting that an equal amount of anticipation be built up halfway through the first act of the film – it simply doesn’t make sense for that to happen.
I strongly suggest you come up with a different inciting incident if it’s to fulfill the function of one.

– “…hires a private investigator…” – this is creepy. No means no, investigating, following and suspecting something is wrong really paints him as crazy. It’s heartbreaking and a shame their relationship didn’t flourish but without a good enough reason (and her saying ‘no’ is not a good reason) for the MC to pursue the relationship further he comes across as mentally/emotionally unstable.

“…the PI ends up following the wrong girl…” – this is a logic flaw. If the Pi follows the wrong girl, he is a bad PI and would have lost any credibility he had. Logically, whatever information the PI finds out should be discarded, and a new PI hired.

– “…must learn to differentiate fact from fiction…” – this is not a description that should be used in a logline, it is too vague and lacks the necessary detail for the reader to know what the MC’s action is and what he wants to achieve.