Rather than divulge the whole truth, Ravio would only share part of it. He wasn't sure if he could even trust her at this point or not. While she didn't seem malice, some enemies tended to hide their evil intent. Yuga did.

"To open up my business! Hyrule is filled with very wealthy patrons!" Namely Link, and namely because Link couldn't finish his quest without the use of Ravio's weapons.