It's painful, at the least.
When someone confesses how they feel for you, and you turn them down.
Guilt is obvious. And, if you care about the person whose 'heart you broke', if that person's a good friend, it just has begun to get worse.
You can't look into their eyes soon. You blame yourself for the tears in their eyes, which you know come by more often now, while they deal with the rejection. You begin to hold yourself responsible for anything and everything bad that happens to that person. You just terribly want to see them happy, and eventually, happier.
You convince yourself that, that's for the best for both of you, while you know that it hurt the other person beyond bounds.
But, in the end, you hope (and well, it's true) it all does pass...
5 years down the line, you move on from the guilt. They've moved on to someone else, or to finding happiness for themselves on their own. It all works out for the best, yes.
