Why can't I comfort people?

Spriha is very sad today. She was very sad yesterday also. She feels nobody likes her. She feels lonely. I think she feels lonely even when she is with me. She likes the company of other people. I believe I might get too boring for her, or even, she does not like too much of me. I won't say I get her, because I can never have enough of her. Its like, even if I spend 24 hours with her, I'd think, why didn't I spend 25. But I know people who want to socialize and be friends with other people, and that, I believe is actually normal. I am the weird one, and I had accepted that long time back. But there are a bunch of girls in our class with whom Spriha wants to be friends with, but she feels excluded from that group most of the time. She always seems sad now and more than often breaks into tears. Here is the thing: I do not know how to comfort people. She talks to her roommate, and I guess she calms her down pretty well, but it should be me right who is always taking care of her? But I never know what to say. I always end up saying that I will always be with her, and that I am always available and that I will always lover her no matter what, but I feel its not enough. Its not comforting enough. And I believe I am losing my edge in making her laugh. Only if I could do that constantly, she'd always be happy. I really really feel helpless right now. She is very sad. I have bring my bubbly smiley girl back. I hope rest of today will be better. I will try my best.