Rejection is never fun.
But rejection also means different things to different guys.
One of my friends was used by a girl who he thought was his girlfriend, only to find out AFTER he took her on a cruise that she was with somebody. it kind of made him stop dating for a long time.
Then, there is my friend who could care less about rejection. He sees a rejection as one step closer to getting laid. And yes, he gets a lot of action.
For me personally, I never really have been rejected because I don't date much. I have been friend zoned by a girl whom we hung out a lot and did a ton of things together. When I asked if we were a couple, she said no but were really good friends. On that, I stopped seeing her because I don't like having girls as friends.
For me, friend zoning is an automatic relationship stopper. And, I guess, rejection would be as well.
And no, if a girl told me that she loved me. I would not be fearful of rejection. My wife/former long term girlfriend tells me that she loves me. But more importantly, I can feel her love for me.