question How can I identify my email going to end user spam folder or not?

[mani0307]

Hello,
I have a question regarding spam email i am doing outbound from last 6 months and sold many domains via outbound but from last one month i have not receiving a single response from enduser even "No interested" and i think my emails going to enduser spam folder, how can i identify that my email going direct inbox or spam folder!

Thanks!