Some "relatively formal" Chinese expressions: 若, 意願

I recently saw an ad in Chinese containing an expression whose two characters are much more commonly found in the reverse order. The ad was for a sublet, and after presenting the general details of the apartment, continued:

若有意願... (ruò yǒu yìyuàn...) if interested...

As in many languages, some expressions are normally used in "relatively formal" contexts (spoken and/or written), but (normally) not in informal conversations.

若 (ruò) here means "if", although practically speaking it is probably only used in written contexts.

有 (yǒu) means "have", but is not a "relatively formal" expression for purposes of this blog entry.

意願 (yìyuàn) here means "interest", and might also be shortened to simply 意 (yì). 
It's used when someone has something to formally offer to someone else, e.g., a job opportunity, or an apartment as described above. Unlike 若 (ruò) , 意願 (yìyuàn) would also be quite normal in speech (in suitably "formal" situations, e.g., when a company representative is speaking to potential job applicants). 

願意 (yuànyì) means "want" or "be willing". If you have been exposed to a fair amount of spoken Chinese, you have likely heard 願意 (yuànyì) far more frequently than 意願 (yìyuàn), but it could be useful to know of the latter.