I think the whole poem is absolutely beautiful. There are a few things you might want to look over, though.
Hair like midnight,
an equal to mine.
Or no, even better,
for mine does not adorn a beauty so fine.
The fourth line of this stanza seems a bit long and it also has "mine" and "fine" in it. The rhythm of the poem slows a bit here, because "fine" is supposed to be rhyming with the first "mine" (in the second line) but there's a second "mine" there. So the same sound is three times in a row rather than the intended two. I'm not sure how to change it, but you did address the reader so you could try something like "for yours adorns a face so fine" or "for yours surrounds a beauty so fine" or some variation of the two.
The figure of a goddess,
wits and brains to boot.
I am in love with you completely,
and that is the truth.
The only problem I see with this stanza is "boot" and "truth" don't really rhyme. I like your message here, so I'm not sure it should be fixed. Maybe try:
The figure of a goddess,
wits and brains as well.
I am in love with you completely,
even if it is hard to tell. (or maybe "its" instead of "it is")
or maybe:
I am in love with you completely,
even if you cannot tell.