French pronunciation rule for "-ient"

Factual Questions
1

Hi
what is the rule when it comes to pronouncing -ient ending of verbs (i.e. the nasal sound)
eg. In the case of “vient”, the verb (venir) ends in -ent. I would pronounce the ending with a nasal sound .
eg. Ils se marient. I would not pronounce the ending. I would ignore the -ent ending.
It’s obvious with “soient” that the -ent is not pronounced.
I haven’t been able to find a rule of thumb regarding the pronunciation of the -ent. When is it required? I look forward to your answer.

2

It is pronounced in all instances EXCEPT the third-person-plural form of verbs.

3

Thanks JKellyMap. Very helpful