Q: È meglio dire:
È meglio dire: Can I smoke here? o May I smoke here は 英語 (イギリス) で何と言いますか?
A: @ravasiosilvia60. I get very colloquial and you wouldn't use it in formal English. I understand or I see are used in a more formal context.
Q:meglio prendere questa strada" は 英語 (イギリス) で何と言いますか?
A: it's better to take this street
Q: è meglio che la smetta は 英語 (イギリス) で何と言いますか?
A: It's better that you stop it...

Q: meglio dentro che fuori は 英語 (アメリカ) で何と言いますか?
A: Better in than out


Q: È meglio "this wait is killing me" o "this waiting is killing me"?
A: Either is correct. I think I would be more likely to say “this wait is killing me” as it sounds slightly more natural.

“The suspense is killing me” is a common saying you could use instead, but your sentences are also good.
Q: è meglio dire "when you need to pass, but he wants to cuddles" o "when you need to pass, but he want cuddles"?
A: La frase corretta sarebbe: When you need to pass but he wants to cuddle.
Q: É meglio dire :
- we have to protect them.
- we must protect them.
Q: è meglio "you're smart like your sister" o "you're as smart as your sister"? この表現は自然ですか?
A: Puoi dire la prima o la seconda (they are both right)