Measuring the waveform of mains voltage using an oscilloscope
The alternative is to buy a cheap differential probe. I had bought one on Ali- Micsig DP10013 and it works surprisingly well. However a handheld scope should have a triax connector and differential input. Many cheap handheld DSO don't have this option, there might be some lurky datasheet that you won't understand at first glance, but then it's too late. Go visit eevblog site for opinions about the DSO you want to buy.
So if the handheld scope is not accessible, then go for HV differential probe.