emmarginate splits the word in the wrong place
stress-doubleDoubling a consonant is how English marks a short stressed vowel. The stressed vowel in emarginate is followed by an r, and nothing else in the word is stressed at all.
heard asemmarginate
spelledemarginate
saidee-MAR-jin-ut
One m. emarginate.
Doubling the m assumes the prefix is em-, as in embed, embark and embody. It is not. The prefix is e-, meaning out of, and the m belongs to the other half, to margo. Put the break in the right place and there is nothing left for a second m to do.
Nearby in the file
emargenate emarginat emerginate emarrginate emarginute emarjinate
The rest are on the word page. All 11 spellings of emarginate.