I'm dubious about these sorts of surreal dialogues because it's hard to tell which bits are unnatural Japanese and which bits are unreal situations.
Anyway ...
好いんだ : This doesn't mean what you think it does.
。。。: Wrong, use ・・・ instead (type / three times with the IME on).
を信じらなかった : This should probably be は信じらなかった.
分かる易い : Don't know what you meant there but in any case the grammar is wrong. 分かりやすい = easy to understand.
俺は, 君は : You are overusing pronouns.
教えれば。。。僕は君を殺すはずだ : Dubious grammar, maybe
教えたら、君を殺さなけりゃならないんだ。
分かるはずじゃないんだ : Don't know what you meant here. Also you are overusing んだ.