How Do You Spell The Word Complection?

It can be spelt two different ways. Complection is accurate, as it much more accurately conveys the syllables, com/plec/tion. Complexion is also accurate, as it stems more from the base word, complex. This is the sort of debate not suited for a question-answer site, but for some sort of message forum. However, you would be better off using Complexion, as that is the more widely accepted than Complection.

The correct spelling is complexion.

The correct spelling is complexion.
Why?
Many words that end in -ion in English come from Latin perfect passive participles
e.g. Navigatus becomes navigation
inspectus becomes inspection
premonitus becomes premonition
etc.
The latin word for "I embrace", is complector, complecti complexus sum
Because the third part, "complexus" has an x in it, the correct english -ion word is complexion.