愛というのはすなわち、戦争のようです。始めるのは簡単。終えるのは難しい。忘れるのは不可能。
There's an attempt, but you'll want to wait for a native speaker to clear that up. A couple of things, though:
1) Something other than a particle has to come before よう; for example, ここに置いたような気がする (I get the feeling I left it here), ドアのノブのような物 (something like a door knob), 山のような高波 (a (tall) wave like a mountain).
2) 簡単 is either an adjective (形容動詞 or な形容詞, to be more specific) or an adverb. In either case it's followed by either な (when it's an adjective) or に (when it's an adverb), so 簡単始まる isn't a very good sentence, but 簡単に始まる is fine.
3) Similarly, 難しい is also an adjective (形容詞 in this case, slightly different), so it can't just modify a verb. You have to make it into an adverb, which would be 難しく.