First, don't take his clothes, cars, supplies, the level of places he takes you to date or hang out, or even the friends he takes you to meet, including occasional phenomena, as the basis of judgment, because these can be disguised or even set for you to see. This is called vigilance.
Second, pay attention to who his friends are. Birds of a feather flock together. What kind of friends are basically what kind of gregarious people are. It's called "knowing a man, knowing his friends".
Third, suddenly ask him to his house. This starts with communication, and we will definitely know each other's residence. After shopping, eating, talking and doing things, the two sides suddenly proposed to go to his house as soon as they met. This has two purposes: home is the most intuitive card that a person can't decorate, and his quality of life can be seen at a glance by looking at the supplies, and everything at home can't be concealed from the overall situation to the details.