Trust is something that a person must earn.
That means that if you want to be my friend and you want me to trust you, then I must know you in person, for a long time (years), and I must have many experiences with you (experiences that prove you were always honest with me).
Then I can trust you.
We should not completely trust anyone that we meet on the internet... these people are strangers.
I'm glad you did not trust the bad man (and you need to know that there are some bad men in every country).