I like the melodies in this one, and the harmony is bitter sweet. It's catchy and the arrangement is good and it's reminiscent of some love themes within a 90's adventure film I've heard in the past. I mean that positively as this writing isn't done in today's cinema. You show moments of light immediately resolving into despair that makes this fit the description accurately. This is tough to pull off in realism. You would have to automate the tempo quite a bit for each motif. Slow down and speed up in a way a string section would play the melodic contours. Moreover, I'm constantly fighting string samples to make them sound more real by automating the volume in the beginning of each note so it doesn't sound so abrupt when they play. There should be a wave in the volume automation for each note as a string player moves the bow on the string when it's a slow piece like this, because it sounds like a producer playing the notes on a keyboard with each note being released as the finger lifts up from the keys. That's what it sounds like for example in the opening lines of the string section. Each note is played the same way whereas a musician playing to your piece would slur these notes a bit more and add vibrato to make sense of the melody. I say this to you, because this is universal among all those that have to deal with samples to create their beautiful orchestral pieces. You kind of have to compose toward the strengths of the sample library as opposed to on paper and trying to make it fit.
If this is a bit long winded, just note that I'm writing to you as if I were writing a journal entry since this is what I struggle with. This is why lately I'm leaning away from bigger orchestral writing as I now just want to write for instruments that I have access to if I were to perform in person. Production and mixing has just a big of a part in the feeling of a piece as the notes themselves. How often I hear a mediocre, uninspired piano piece on Youtube with much following simply because it audibly sounds well. And no one wants to hear Beethoven's Moonlight Sonata via Midi. To the general public, simply having superb production and realism in the timbre of a piece will alone draw an emotional response. The fact that you can convey emotion in your piece here shows how strong the melody and arrangement is. If only we can hear actual musicians playing your piece would we find the flaws in the composition to be beautiful as human.