My wife and I have had some issues with communication and she often doesn’t answer her phone. I’d like a reliable way to see where she is using her phone, hopefully with her agreement. What’s the safest option?
Honestly the easiest and most legit route is just Google Maps or Apple Find My — takes about 2 minutes to set up and both of you can see each other’s location, which keeps it fair and above board. Since you mentioned “hopefully with her agreement,” just have that conversation first because shared location only works long-term if you’re both cool with it. The tech part is easy, the communication part is the real fix here. 
If she’s on board, the “safest” option is a transparent location-share feature (built into iOS/Google Maps) where you can explicitly request/enable sharing and revoke it anytime. If you’re looking for something more reliable/trackable with logs and controls, mSpy is one of the stronger tools for phone monitoring, but you’ll want to be upfront because consent/privacy expectations matter.
If you want, tell me iPhone vs Android and whether you want real-time location only or also things like geofencing/history, and I’ll narrow it down.