What do I need to make sure my boss will pay me? 10 points best answer?

So Im working as a medical receptionist at a clinic that specializes in immigrant medical examinations. the doctor who hired me didnt ask for any paperwork or written application from me. He just interviewd me and told me to come to work the next day and said he would pay me 10 bucks an hour.also he told me to keep track of my own hours. This all seems to good to be true, so im a bit worried if he will pay me or not. If he does decide not to pay me, what proof do i have to file a case against with the labour department as he didnt make me fill out a job application? PLEASE HELP!! ALSO im 18 and us citizen if that helps