As it happens, boni enim magistri estis is what I wrote. The sentence is from the answer key to my Latin Exercise Book.So, would you rather say boni enim magistri estis?
(Perhaps estis enim boni magistri? Or vos enim boni magistri estis? So my question will be this: what is more natural, basic or common?)
I thought about emphasis...As it happens, boni enim magistri estis is what I wrote. The sentence is from the answer key to my Latin Exercise Book.
Your other two versions are good as well, but be aware that the one including vos is emphasizing "you"—so it's like "you are good teachers (as opposed to some other people, for instance)".
Most often, but not always.Is enim always supposed to come in the second position?
(There are even a few instances of it coming first, but that is really very rare and non-classical.)Enim can come in third position when the two words before it are so closely linked as to form one prosodic unit. Example: aequum est enim, where aequum est is really pronounced as one word, aequumst. It sometimes not only can, but must be this way; for example a preposition like in or ex can't be separated from the following word by enim (e.g. you don't say in enim agro but in agro enim).
Regarding boni magistri enim estis specifically, I think it's possible for boni magistri to be taken as a unit (maybe more a unit of sense than a prosodic one) but it sounds a little unusual.