What should I do about a female colleague who shuns me and refuses to return my greetings, despite my continuous attempts to reconcile with her and my congratulating her on her engagement and marriage, while she has persisted in shunning me since my own engagement and refused to congratulate me on my engagement and marriage?

You must continue to greet your friend and visit her and appease her by all means, for Allah, the Almighty, says: "Nor can goodness and evil be equal. Repel (evil) with that which is better: Then verily he, between whom and you was enmity, (will become) as though he was a close friend." If she continues the estrangement after that, you will be absolved of sin, and she will bear it, for the Prophet, peace and blessings be upon him, said: "It is not lawful for a believer to forsake his brother for more than three (days). If three (days) pass and he meets him, he should greet him. If he returns the greeting, then they both share the reward. If he does not return it, then he has incurred the sin."