How to convert binary string to string. json_encode binary string returns false

I have read, that b in front of something means binary.

I am receiving text field from MS DB. I am using Laravel and when I die dump (dd()) I see:

b"""
My big text
"""

If I create simple string and dd() it I see:

"My text"

The problem is that json_encode() returns false on this b-String, but everything fine with simple string.

Could you please tell me how can I make it simple string?

P.S. I have tried unpack() -> unsuccess

via Chebli Mohamed