What is the ruling on a Muslim woman inviting her Christian male colleague to embrace Islam?

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

Women are subject to certain limits that must not be exceeded under the pretext of practicing Da’wah and/or good intention. Accordingly, a Muslim woman may invite a non-Muslim man, with whom she was forced to meet under compelling circumstances, to Islam, if and only if she complies with all applicable Islamic regulations, including wearing Hijab and avoiding meeting in private and softness in her speech with him.

This opinion is supported by the story in which Anas narrated that Abu Talhah proposed to Um Sulaym and she invited him to embrace Islam, setting this to be her dowry. In response, he embraced Islam and married her.  [An-Nasaa’i]

Allaah Knows best.