Okay, here is my go at it, with abbreviations expanded.
I have kept the scribe's spelling variations (including the unusual "w" in ungwibus), but I question "cira" which refers to wax ("cura" makes more sense in this context but maybe "cira" has other meanings in medieval Latin that I don't know about):
brachia no[n] mi[n]as cum lustra[t] luna gemellas
vngwib[us] [et] ma[n]ib[us] cu[m] f[e]r[ro] cira (cira seems odd, could he have meant "cura?") neget[ur])
nu[m]q[uid] portab[is] ap[ro]missio[r]e p[er]itu[m]
brachia non minas cum lustrat luna gemellas
ungwibus [usually unguibus] et manibus cum ferro cira/cura? negetur
numquid portabis apromissiore peritum
I was not sure if he meant "numquid" or "numquam" when I first read it, it is written more like "numquam" abbreviation, but some scribes wrote both abbreviations almost the same.
Note that this writer uses the end-tail to stand for a variety of letters, including "m" and "r". Some scribes use the tail to point at the exact spot the letter is missing, but that's less common than what this scribe does, which is simply to swing the tail over, like a macron, without pointing at any particular spot (the "pointer" doesn't line up with the missing letter).
Also, the letter than looks like a leaned-back "b" in "ungwibus" I have noticed is almost always u/v in Latin texts. It's actually a "v" shape with a very long leading serif.
Sounds like something from an astrology text, with the information about the moon and "twins" (Gemini).