Asking someone out

To be practical, it happens only when a guy asks a girl for a date.. its really very less likely to happen in the other case! I think the meaning of "I don't know" varies from person to person. Say, some girl may say because she needs some time to make her mind, some may say this because she may be wanting you to move around her, give her importance, some other may say this because she may be too shy to agree for a date, and so on. There may be many reasons.. for older people have said, its very difficult to understand a lady!

My opinion is as follows: if it's a guy who answers "I don't know", then it's a polite refuse, or he is too shy. But if it's a girl, then it's surely a refuse!