Certainly, visible changes didn't happen, but... (originally 確かに目に見えた異変は起きていないが。。。)

...however, regardless of that... (originally それとは関係なく)

...I have no doubt that this kappa was a strong interference in this girl. (originally あの河童がコイツに深く干渉したのは間違いないのだけど)

So you remember that girl, don't you? (originally 彼女のことを覚えていないと？)

Firstly, (originally だからそもそも)

This is the first time I met that girl.

That's a lie, isn't it? (originally そんな筈は、無いのだがね)

You're so obstinate... On what basis are you... (originally しつこいな。。。一体何を根拠に。。。)

Don't know...? Have forgotten...?

Considering all that, you, talking to Nitori, are... very happy. (originally その割には、にとりの話をするあなた。。。すごく幸せそう)