But
Three ways to say 'but', from neutral to complaining, learned on one rain sentence.
demo
but; even so
でも
Opens a sentence or a turn that pushes back against what was just said; works the same in every register.
ame da ne. demo, iku yo.
It's raining, huh. But I'm going.
雨だね。でも、行くよ。
ame desu ne. demo, ikimasu yo.
It's raining. But I'm going.
雨ですね。でも、行きますよ。
Same sound as noun + demo ('ocha demo' = tea or something); sentence-initial position tells them apart.
-kedo
polite desu kedo / -masu kedobut; although
けど ですけど / ますけど
Ends the first clause and contrasts it with the second. Left trailing, it softens a statement ('chotto takai kedo...') or sets up a request ('chotto kikitai n da kedo...'). Fuller keredo; formal ga.
ame da kedo, iku yo.
It's raining, but I'm going.
雨だけど、行くよ。
ame desu kedo, ikimasu yo.
It's raining, but I'm going.
雨ですけど、行きますよ。
A trailing kedo ('sumimasen kedo...') is a soft opener, not a contrast.
-noni
even though; and yet
のに
Contrast with surprise, complaint or regret: the result isn't what the first clause should lead to. Nouns and na-adjectives take na noni. Left trailing it's a complaint ('itta noni!' = 'but I told you!'); after -tara / -ba it means 'if only' ('motto hayaku ittara, maniatta noni').
ame na noni, iku no?
You're going, even though it's raining?
雨なのに、行くの？
ame na noni, iku n desu ka?
You're going even though it's raining?
雨なのに、行くんですか？
Can't end in a request or plan ('...noni, ikou' is wrong); use kedo there.