## and I did not wish to write them with paper and ink ##

This can be translated "but I did not want to write them to you in a letter."

## face to face ##

This can be translated "actually with you"

## joy may be made full ##

This can be translated "joy may be complete"

## The children of your elect sister ##

Here John compares this other church to a sister. And the believers that are a part of that church are compared to children. This emphasizes that all believers are a spiritual family. (See: [[rc://en/ta/man/translate/figs-metaphor]])