Under is indeed the correct spelling.
Some example sentences are:
The bleach is under the sink.
Put this thermometer under your tongue.
Have you looked under the cushions?
Yes, "under" is the correct spelling.
The duration of Under Your Spell - film - is 1.03 hours.
Under Your Spell - film - was created on 1936-11-06.
Under Your Spell Again was created on 1959-07-13.
Under a Spell - 2009 was released on: USA: 2009
Under a Spell - 1925 was released on: USA: 5 January 1925
In Word, the spell-check feature can be found under the review tab in the proofing group.
Related to being under an actual magical spell, it means that someone is captivated by another person, or influenced by them.
To hold under or as if under a spell; enchant or fascinate.
Under Your Spell - 1936 is rated/received certificates of: USA:Approved USA:Passed (National Board of Review)
it is about a girl under a spell
to place under a spell; be witch
HUGELY unlikely.