I suggest a silent strategy. Destroy the smoke detection system in your house. Close your windows and shut the blinds. Then cover her mouth and stab her. If stabbing her doesn't work, then use fire. Then put out the fire. Remove any traces of evidence as you will be convicted and put into 17 years of jail time. Then bury her body somewhere far away from your home. Then, move out. At least 100 km away from the body.
If this takes place in a public area/building, throw the smoke grenade and put on your thermal vision goggles and acquire sight of the lady. Then repeat Step 2 or 3. Then, drive away from the city as fast as possible regardless of the innocent civilians around you. The police are most likely chasing you right now as you do these steps.
I suggest doing this with a partner.
If this doesn't work, frantically try your strategy.