अनुबाद - अंग्रेजी-जर्मन - (Our) relationship was very very close, so I clearly thought so.

Please see my post under the original Japanese language request for further details about this translation.

If you want "meaning only", better translation (in my opinion) would be:

Unsere Beziehung war sehr intim, also habe ich das natürlich angenommen.