Few points which would help to know saint’s reality are –
1. Given spiritual atmosphere, the spiritual love that saint possesses gets revealed in the forms of physical states of ecstasy, tears and so on.
2. Your faith in God gets stronger and stronger, day by day.
3. You attachment to worldly objects and persons shows gradual reduction.
4. You develop liking for God and subjects related to God.
5. Your doubts gets settled.
6. You find concentrating on God much easier in his presence than otherwise.
Although whatever is stated above sounds all right, you need to spend some time with any saint. You must follow the spiritual exercises that he wants you to and only then you can decide whether he is a saint or not.
Few things that saint can do are :