First off, Incredible job with excellent technique. It definitely has a strong romantic sense to it. A couple little things that come to mind when viewing it though: the background coloring is a little confusing to the eye. Clearly there is a backlight of some sort but the array of colors makes it fairly hard to tell if it is lamps, sun shining through trees, etc. Especially with the blue shades in the background, it feels like they could almost be standing in front of a stained glass window rather than a park.
It is also clear that the ground is wet given the reflections it is giving off, but the reflections make less sense because of the background as it is reflecting light sources that don't appear clearly in the background.
As for the two strangers kissing, they look great, the only thing I could think of would be to add a little more definition to the man's face.
Other than that, I would suggest just a little more contrast in the umbrella so it stands out a little more from the background (but not too much).
Again, great job! this is one of my favorites!