how to respond to these lines girls say when you approach?

'Sorry i have to go'

'I don't wanna talk to you,please go'

'I am not interested in these kind of things(relationship,dating)'

please also talk about any other approach tests you have experienced and overcome.

also i want to know how to tell if a girl who says these lines is not interested in you or you just have to persistent and approach her again.

Thanks.