friendship or love?

if u hav a friend who's been with u practically ur whole life how wud u decide if its friendship or love or how do u decide to name it sumthing

this is the story of Elizabeth and her life as she lives it. to her Chase plays a very big part in her life and they both Care about each other immensely
they can complete each other's sentences and cAn even know if the other one is sad even through just a text message
a few yrs ago chase's dad got a transfer n his family shifted out. but after after 10yrs he's back to resolve a fight n win his old bestfriend back( so he says :p) ...... but knew the moment he enters her house he realizes he's in for a big problem sumthing noone can help him with.......should he be happy with just keeping .Elizabeth as an old bestfriend or should he listen to his heart n tell her about his old. lifelong crush on her? n how will it effect their frienship