If someone unsubscribes and later signs up for my newsletter again, will they get my emails?

Yes. Signing up again counts as giving consent again, so Wcart switches the address back to Subscribed and updates its consent date. They will receive your next campaign.

You can check it on Marketing → Newsletter Subscribers: search for the email and look at Status and Consent. If you need to do it yourself, click Resubscribe on their row.