Questions & Answers about Я не уверен, будет ли повышение в этом месяце.
Because the sentence after it (будет ли повышение в этом месяце) is a subordinate clause (an embedded yes/no question). In Russian, subordinate clauses are normally separated by commas:
- Я не уверен, …
- Я знаю, что …
- Я спросил, будет ли …
ли marks an indirect yes/no question, similar to “whether / if” in English:
- Я не уверен, будет ли повышение… = “I’m not sure whether there will be a raise/promotion…”
In indirect questions, ли usually comes right after the word that’s being “questioned” or emphasized—very often after the verb:
- будет ли = “whether there will be” You can sometimes move it for emphasis, but будет ли is the most neutral here.