If you have connected your own Gmail or MS365 account to send emails through Hub, then you will see the emails in your Sent/Outbox folder. There isn't a good way to tell if something was automatically marked as Spam, and if you are using a connected account then we have no control over your personal sender reputation (in all likelihood your email reputation is very good). I can assure you that if you are not sending via a connected account, Hub's own email reputation is very good as well and the vast majority of emails make it to the inbox. However, there is no guarantee that every email will make it to someone's inbox vs their Spam folder, regardless of whether or not you have connected a personal account.

If your primary concern is something being marked as spam, then you can click the Disable click tracking and automation button on the email so that there is no tracking info in links you send in your emails via Hub, but, as the name suggests, this will give you less information on interactions with your emails. This can potentially decrease the percentage of emails that get sent to Spam, but again it's impossible to guarantee.

Deliverability to anyone at a bank or any other organization will depend on that organization's own email rules, but other than that I don't know that it would be any less likely to be delivered to that person's inbox than any other person's.