How do you know if a girl isn't just doing a friendly flirt with you and instead actually likes you?

if the girl makes fun of you playfully like....

wow you would....

did you really just do that

but if she likes you she will talk louder, she will always be somewhere near you she will ask you questions and talk just nomally to you like you are one of her friends but becareful because you could get this mixed up with just being friens so make it so you tell her you might like her back too and see where it goes from there if she kinda backs down a little she may just want to be friends but if she doesnt well there ya go!!!