As always, anime-sharing is a decent source for untranslated Japanese games: just search the game's code (in this case RJ01012446). They use paid file hosts so speeds are generally terrible, with Mexa being the least bad at 1Mbps.
The game works fine with the Xunity.Autotranslator, though I'd recommend holding off on playing it for now. There's still more stuff the dev wants to add (for example, outfits are in the shop menu but haven't been implemented yet) and we'll probably get an English version eventually too. Like, the version of Amu-chan that got made into English is far more robust than the JP version I had played months before, and I feel Rina-chan will definitely benefit from a bit more development time.
And for something I know a bit less about but will still talk about anyway, the title "わからせりぃなちゃん" (Wakarase Rina-chan) means something along the lines of "Making Rina-chan Understand (her place)" or "Teaching Rina-chan a Lesson." Wakarase comes up often enough in porn works and does represent understand, but will often be mistranslated into titles such as "Getting to know Rina-chan" or "Rina-chan Understands" while the girl (in this case, Rina-chan) is the one who is being given the understanding. "Instructing Rina-chan" is probably also viable if the translator is trying for a title that sounds less rapey.
