Need advice about affiliate marketing

I did a lot of research and studied new good techniques to promote things
but I'm confused and don't know what will be the best affiliate offer to promote.
I want something that is converting, in- demand, pays good and I can be sure that I will get paid without dealing with untrustworthy affiliate programs.
any suggestions?

thanks.

You can check clickbank, they're one of the biggest affiliate networks but it's quite difficult to get accepted with them