I know two scenarios. Both people I know personally. One person I know met a guy from New York online. They decided to meet, he came to California to meet her and have been here since. THey are now married, and have been for 3 yrs, and have a child. They have had to go through all the pains of getting to know one another, but they are still married. He lied about everything, but in the end, none of it mattered because they really loved one another.
Another scenario someone I have known since childhood. She too met someone online. She brought him home, they had sex, and he stabbed her 18 times. The ONLY thing that saved her life was the fact that she was overweight. Ironically he got off because he said that he was defending his own life from her trying to force him to have sex with her. He got off scott free for almost killing her.
Always be safe. You never know. But that is true for people that you meet on the street day to day. Everyone is a stranger until you get to know them, their world, their family and friends. Even still you cant know everything. Use your judgement and if you are a Christian, trust GOD will lead you to who HE wants for you. That is always the best option anyway. We can never choose better than HE can.