Regarding the swearing, "usanksai", maybe "this guy seems fishy", or "woa that guy seems dodgy" would be nicer?
Page 11; Cost of purification is 300,000 Cents in Japanese, not 30,000, though the 30 Million Yen in the speech bubble below is consistent and correct to the 300K Cents
Page 15; "That old man is my grandpa", it's a little difficult to get what the author was striving for, but based on context maybe it should be along the lines of "I can't believe you, you and Grandpa both!"? (Upset that her betrothed is being used by her gramps and by the shady estate agent just because of a desire to raise market values? And maybe at the property owner(s) for trying to shift dodgy property and add their daughters to Well's harem?)
Page 30; I believe this should be more like "after performing 4 purifications, I was given this splendid mansion as a reward" this makes more sense financially (4x300KCents = 1.2MillionCents, assuming that the mansion he was given was somewhat smaller, plus haunted cutting its value further, getting a Baron level mansion for only 3 purifications seems cheap regardless of haunting and that would remove the implication that it was the 4th mansion he was shown and so should have suspected it was haunted)
First mansion has an estimated value of 10 Million cents, this is only 10 Platinum and he has over a thousand left (probably close to 1500), why go the the extra level of effort to spend time purifying multiple mansions just to save yourself a couple of platinum in that state? Seriously, was this just chapter padding? Or maybe to establish Elise's attachment to Well in the reader's head?