B”H Thank you for your help.
Is it allowed to delete emails from Jewish fundraising sources if we are not sure that the sender is legitimate (meaning they are not a Jewish fundraiser, but someone impersonating a legitimate fundraiser). In case it turns out the email was legitimate, and it was deleted and the persona can see somehow through technology that the receiver unsubscribed/deleted the email- does this break any halacha (causing someone pain or feeling rejected?) If this could be answered privately, I would appreciate it. (Thank you so much for the help with both the halacha questions and the interpersonal questions, they are helping so much BH)
There is no problem deleting these e-mail. The first reason is as you write, who says that the sender is legitimate. Secondly, although there is an obligation not to turn away a poor person who asks you specifically for tzedakah, mass e-mailings are not included in this. This is because they don’t mean you specifically, rather they are asking anyone who will answer them. Therefore even if the e-mail was legitimate you may delete it. You may give to the organization is you like, but you have no obligation to donate specifically to them.
Although other might benefit from reading this answer, it will be sent privately as per you request.
Have a good Shabbos