んだ => Let's... N4
Order
もの/もん/んだもの/んだもん => because; indicates reason/ excuse/ dissatisfaction N3
なんだか => somehow, somewhat N3
Vague
んだが => Start the story N4
How to say the beginning
んだった => If... (express regret) N2
Regret
べつだんの => particular; special N2
Description
んだか => Confirm and provide information N4
Confirm
とんだ => unthinkable; unimaginable; inconceivable; unexpected N2
Beyond expectations
なんて…んだろう => how (beautiful, etc.); what a ~ N3
Exclamatory
~いかんだ / いかんで、~ /  ~いかんによって、~ => It depends ... N1
Related, corresponding
んだって => Hear that~ N3
Information, Report
たいへんだ => It is hard, serious N4
Evaluate