page 3 - "до свидания" directly translated to "until meeting/date", normally means the same thing as "goodbye" with similar connotations compared to just "bye". Not at all weird here, I'd even say that it could be a way to characterise her if I didn't know any better about this shit manga.
page 25 - "что не так?" sounds a bit unusual and means "what exactly is wrong?" (not particularly polite), in contrast to, for example, "что-то не так?", meaning "something wrong?" or "what's wrong?. It doesn't sound right when it's not a response to someone complaining or something.
page 26 - see page 3, also god is this manga ugly
page 27 - "правда" is a noun that means "truth", but when asked as a question, it means "is that true?", which fits the translation here.
this chapter is really fucking ugly, guess the author can't draw anatomy for shit unless it's porn