आँत्वान
I speak French, Hindi and English
I know how it should sound, thanks to the "Chandra Bindhu" it has the nasal sound "An" like in "je pars EN vacances" and the end sounds like "twaane" and not "tony" or "tw-an" like in the two originally proposed versions
The two versions you proposed sound like "un-tony" and "ene-tw-an" respectively and what tiraj proposed sounds like "un-tw-an"
Voilà, voilà, j'espère que cela vous sera utile, même si je suis conscient de répondre avec 6 mois de retard
P.S: My french boyfriend's name too is "Antoine" ;P