How can I invite my good-natured colleague and guide her while adhering to the prohibition of khalwa (private seclusion with a person of the opposite sex) and looking at a non-mahram woman?

It is forbidden to be in seclusion with a non-mahram woman and to look at her. She can be advised by speaking to her while she is veiled and not in seclusion, or by gifting her a beneficial book or audio recording, or by writing advice for her, while avoiding temptation.