Personally, I think it is due to the fact that it shows more commitment and leaves one vulnerable. The words kind of leave a person open, in a way that rejection can be hurtful. The words are too strong and have a deep meaning, regardless of when or where they are used. To me, saying the words makes me feel like am an open book, and the person knows me inside out. I get afraid I may end up getting hurt for being that open, and sort of letting people into my heart is a bit scary.
i think its sometimes difficult to say i love you to a guy that you know you really like, but theres just little quirks and things about him that make you hold back from letting him know that your commited. sometimes you just have to dig a little deeper for the right guy and get comfortable.
When you're ready to say it, it is not scary if it is given like a gift to someone unconditionally. Maybe it will hurt if the person doesn't say it back a little bit, but you should say it because it's how you feel and you want to let the other person know that and it's not about you being rejected. It's about giving someone you love a gift of your heart. Think of it that way and you won't be afraid. Plus if you have confidence in yourself, you won't be afraid to say it or not have it said back to you right away.
You're right. It's hard for some people to say "I love you". I'm certain that if I would have said it when I had the chance, I wouldn't be alone tonight. If and when the opportunity ever comes up again, I will say it.