However, it's more likely it was just a mistake, because words ending in ant or ent (or ance or ence) are notoriously tricky to spell.
The only way I know to do so is simply to learn the word by rote, or connect it to another word in the same 'family' whose spelling I know. (For example, if I can spell coincidental, which has the emphasis on the fourth syllable, ent, then I can spell coincidence, even though the ending ence is not pronounced clearly.)
If we know the Latin root of the word, it may help, but as Gorgonzola says, it's not particularly useful to ask people to learn Latin just so they can spell better in English. On the other hand, I think knowledge of Italian spelling would also help here, as this table of Italian verb endings shows us. Gorgonzola has a long list of spelling hints for these classes of words, and I think the page makes a great job of trying to get some sense into this tricky topic, but I think I'd be more likely to just look in a dictionary if I got stuck on a word, as the Aries site says:
The spellings -ent, -ence, -ant, -ance are especially tricky. There are no rules. We can only give you some examples and advise you to check such words in a dictionary if you aren't sure of the spelling.
By the way, here's a site listing 533 words in English that end in ant.