A relationship between a girl and a guy can be labelled as "best frens" when they have a mutual relationship, respecting each others space and privacy, prepared to seek each other's wisdom without any inhibitions, realise that though they have their individual lives, they are always there for the other.

The "best fren" label will be given when these two, out of the above factors find themselves making love (not just sex) as a ordinary course of events leads them to bed to express their genuine feelings of care and concern. No obligations after that. Love is mutually shared and that's their secret, like all other secrets they share.

Life then continues as usual, both giving the other the due respect and friendship. That's called "best frens".