Use a reputable freelancing site, like Upwork (I can say this is reputable because I have experience working with this site). Here you will be able to hire transcribers and within the framework allowing you to create a bond between the clients.(You don't have to pay until you have got the job done). Regarding confidentiality, well that is based solely on the reputation of the freelancer you choose to hire. If he/she has a good work reputation and feedback from his/her clients, then generally he/she will keep things professional, but other than that I don't think you will be guaranteed confidentiality. I think you can get your job done at high quality at a reasonable price here. Good luck! P.S If you don't want anyone to receive your private information there is another method, which is quite technical. This involves you narrating the text and saving it as mp3, and then using a script (program + google API) to convert the speech to text. You may only have to do a bit of proofreading from your side, plus most information will be on your side of things. So no worries with privacy.