How do I determine whether "Global Scientific Journal" is reputable or not?
Although the question may be flagged as &quot;off topic&quot;, I think that it is essential to expose predatory journals nonetheless. Hence my answer is:
Yes, most probably Global Scientific Journal - GSJ Publication is predatory (which is worse than non-reputable).
My assessment is based simply on the reputable Beall's list  here (updated two weeks ago, 18 Aug 2019):

Here we include journals that were not originally on the Beall's list, but may be predatory.
Global Journal of Advance Research on Classical and Modern Geometries
Global Journal of Research on Medicinal Plants &amp; Indigenous Medicine
Global Scientific Journal - GSJ Publication