Wait, what? You need to send a report every new lesson you go to?
I think the iĝ affix specifically denotes becoming/a change in state, so 'be interested' would be wrong. I think be interested would be interesu where interesiĝu has an extra layer of meaning that makes it get interested, become interested, etc. (I don't know which translation(s) are currently accepted!)
Thanks for pointing that out. It's not quite true that "the iĝ affix specifically denotes becoming or a change in state." Basically it removes one of the actors in a verb. That is, if you look at a word like "interesas" - there are two main actors: the interesting thing and the interested thing.
- "Poezo interesas min".
- Poetry interests me.
Adding "iĝ" simply allows us to make "min" the subject
- Mi interesiĝas
- I am interested.
If we want to say what we're interested, in, we can say that like this:
- Mi interesiĝas pri poezio.
- I am interested in poetry.
Nowhere are we saying that our level of interest is changing.