A lot of people are fairly dubious about asking for proofreading. This is mainly because a great deal of people want their academic work to be their own and they fear that a proofreader will change their work enough for it to be considered plagiarism!
This is something I strive to not do. When I proofread work, I only ever change certain words. “Particular” becomes “specific”, and other things of the same kind. I might change contractions such as “It’s” to become “It is”, but that’s because an academic thesis needs to be formal and they expect you to use longform work; in other words, no contractions.
Apart from that, I won’t change your tone or your work. I don’t claim to know everything, apart from the conventions of written English. You know more about your subject than I do and I’m not responsible for correcting your facts. If there’s an inconsistency in your work, I’m going to leave you a comment pointing it out, but I trust you to have your facts and results in order.
I’m not here to research for you or write it out for you. Don’t worry so much about asking for a proofreader. I won’t be making any changes that would be considered stealing from me. Just let me know what you want and I will do what I do best - proofread!