Even though I'm not a native English speaker, don't rush to prejudge me. I've got an intermediate level of English (around B2) and I just want to test and improve my skills by being a beta-reader. I think it will be fun.
However, I write my own stories, so don't expect me to always be ready to check yours. Moreover, now I'm a senior, so I can be also busy preparing for my final exams.
In case if I'm REALLY interested in your story, as well as just looking through for typos or any other mistakes, I may help you with the plot (but only if you'd like to; don't wanna be intrusive). As for mistakes, I'm honest, but even though there are many of them, I respect your feelings as a person and a writer, and, if you respect mine too, I'll try to not to be very harsh on you.
I'll warn you, that I don't like having many plots and twists messing up in my head, so I can refuse to beta-read your work right away if I still haven't checked the other one so far. A maximum of two at the same time will be more than enough.
And finally, just don't push me too hard and ask to do the impossible things, like reading a novel of 20 chapters in one evening. We're all human beings and I've also got a right to have my personal life.