How can one deal with a female colleague who shows hostility and jealousy, and causes verbal harm both directly and indirectly?

It is a Muslim's duty to love and hate, to be angry and pleased for the sake of Allah. This is one of the strongest bonds of faith, not merely for personal whims. Among the good manners of a believer are pardon, forgiveness, and responding to evil with good, as Allah Almighty says: "Repel [evil] with that which is better..." (Quran 23:96). Slandering, backbiting, and harming believers are forbidden, for Allah Almighty says: "Woe to every slanderer and backbiter" (Quran 104:1), and "And those who harm believing men and believing women for [something] other than what they have earned have certainly borne a slander and a manifest sin" (Quran 33:58). Likewise, injustice and exaggeration in it are not permissible. Allah has warned against a lack of justice due to hatred, saying: "And let not the hatred of a people prevent you from being just. Be just; that is nearer to righteousness" (Quran 5:8). And injustice will be darknesses on the Day of Resurrection. The advice is to apologize to your colleague and ask to start a new relationship. If she accepts, that is good; if she refuses, you will still be rewarded.