I actually thought of starting with Arien qualities but...
Being an Aries girl, believing my Aries guru, I never gave a thought about Archer (Sagittarius). Even in Love Signs she mentioned about Saggy being disloyal more or less even after wedding. But recently I saw this Orange helped me understand why Aries-Saggy are magnetic to each other.
So firstly lets meet the perfect Saggy of the movie, the Hero "Ram". His fire sign sparks can be observed from the first when he screams and comes to destroy his best art work. The heroine of the movie "Jaanu", our Aries, gets introduced with innocent excitement and enjoying love story. As usual Sagittarius gets attracted to Aries instantaneously as LG mentions. Girl's Arian impatience and impulsiveness and eager to be in love makes her look for 3 guys without any thought. But with Sagittarian in line, not so easy for Aries. His interests of sky-diving, wild life photography and Graffiti are typical of a Saggy. He proposes her but with her Arien individuality, she thinks she can toss him out but as he is lot before her in karmic wheel she seems only cute even when she is serious. Man's strength and courage as usual gains her interest more than humour, golf or looks and her anger is never permanent. Another impulsive decision to go out with him. She is never sure of her looks and feminity. His surprise of an encounter with lion, enough lit her Mars enthusiasm and propose herself. Now comes the point, Archer and his truth. He cant lie. Thats what is his unique quality. Flat declaration about his idea of “love for only few days”. But he is not a weak chap to let her go. Both cant live without love (along with Leo). His reasoning ability kills her. Her idea of a single woman man (rama) changes with his remark “I never loved two girls at the same time” (Ofcourse he is definitely not a Gemini). But the sparkling ideas of Saggy makes her see things in a different perspective. Definitely the sky diving birthday present makes a strong impression. But she cant let herself losing in an argument and so never gives up in proving her faith in love stories, infact fairy tales. His flashback truly portrays Saggy's love for freedom, friends, ex-gfs and "truth". I doubt the other heroine to be Scorpio for her demands. But never mind, exactly the way it was explained in "Love Signs" he runs away from the informal betrothal, and feels relaxed when his freedom is won back.
When our Arien finally sees him as a perfect man, to be precise her knight in shining armour rescuing her (princess), wont push around and expresses her love. She accepts all his ideology but not the short term love, and with all Arien determination puts her agenda. He cant lie. He simply cant. So she walks away. Believe me when LG said its easier to catch a bandersnatch than her, she meant it. But after all he is under a mutable sign and more adaptable and flexible. She is under Cardinal and has to lead. He analyses himself and her, well to arrive at an optimized solution. And only an Arien girl could understand what he meant, "Jaanu" did, but not without her thousand innocent doubts. Inspite of the messed up (may be just unconventional) mind of the guy, truly it must be 5-9 relationship for her to accept him.
That's not the end of the story, Aries girl could allow him to wander and explore but not without financial steadiness. Remember, she needs a man who is always greater than her, not a MCP. So he must earn, not to gain her respect but for the sake of her respect. Another icicle when she wants him to leave Graffiti, but he couldnt let her go for the reason of his ego (remember he is a Saggy, not a Leo) and ends in a quest for immense sea of love with “Jaanu”.