It's understandable that you felt a sense of betrayal and disappointment when you discovered the truth about your online friend. It might be difficult to accurately judge someone's sincerity and intentions while connecting and making acquaintances online. It's crucial to proceed cautiously when entering into online interactions and to remember that people aren't always what they seem to be.
As in everything in life, in any field in which we operate, we will always find fakes and scammers. You always have to be alert.