Questions & Answers about tā quèshí huì chàng.
确实 means indeed, really, or it is true that. It adds emphasis and confirms that something is genuinely the case.
So 她确实会唱 is stronger than just 她会唱. It suggests something like:
- She really can sing
- She truly knows how to sing
- She indeed can sing
It often sounds like the speaker is confirming something, maybe because there was doubt before.
Here, 会 means know how to or be able to because of learned skill.
In this sentence, 会唱 means can sing / knows how to sing.
That is different from some other uses of 会:
- learned ability: 我会开车 = I can drive / I know how to drive
- future likelihood: 明天会下雨 = It will rain tomorrow
- possibility in some contexts
In 她确实会唱, the most natural meaning is She really can sing or She really knows how to sing.