I'll assume that this is a platonic friendship between two people, irrespective of gender, language, religion, nationality, time-zone and media (as in, virtual or real). In this case, it would be -
- Acceptance for each other, as long as those are good virtues
- Care for each other
- Godly support (if it is a Christian friendship)
- Emotional support: a shoulder to lean/cry on, if the going gets tough
True friendship is friendship with boundaries: no financial support, no sacrifices to the point of absolute ruin, no bartering, and no demands. It is logical and can be perfectly understood by a third person.