A Confident Guess
でしょう states what you think is probably true — more sure than かもしれない, less sure than a flat statement.
- 明日は晴れるでしょう。(It will probably be fine tomorrow.)
This is the sentence you hear every night on the weather forecast.
Formation
Attach to the plain form; drop だ from nouns and な-adjectives:
| Type | + でしょう |
|---|---|
| Verb | 降るでしょう |
| い-adjective | 高いでしょう |
| な-adjective | 静かでしょう |
| Noun | 学生でしょう |
だろう is the plain equivalent — same meaning, casual or written.
The Second Job: Seeking Agreement
Said with rising intonation, でしょう stops being a guess and asks the listener to agree:
- これ、おいしいでしょう？(This is delicious, isn't it?)
Falling intonation = probably. Rising = right? Same word, and only the tone separates them. Casually this becomes でしょ？
Compared with the Other Guesses
| Pattern | Confidence | Basis |
|---|---|---|
| かもしれない | might | bare possibility |
| でしょう | probably | general expectation |
| はず | should be | a specific reason |
| に違いない | must be | near certainty |
Politeness Note
でしょう is polite in form, but using it about the listener can sound presumptuous — you are telling them what is probably true of them:
- △ 疲れているでしょう。(You're probably tired.)
- ○ 疲れていませんか。(Aren't you tired?)
With rising intonation seeking agreement it is friendly; as a flat prediction about someone, less so.