Is there any way of knowing if the date was modified?

My sister was supposed to send me a very important email by wednesday and she sent it thursday, claiming that she hit "send" but the email was not sent. I thought she had simply forgot and she showed me a draft of the email that was made on wednesday as proof that she did send it. However I suspect that she changed the date and time of her iPhone, created the draft, and then changed it back. Is there any way of knowing whether she did or didn't do this?

If your e-mail received it Thursday and she claimed to have sent it Wednesday, there could have something wrong with the e-mailing client to which there was possibly an issue going on at the time of delivery that delayed the email from being sent which would not have been your sisters fault. This sort of thing happens to me all the time with clients and contractors e-mailing me their bids and receipts. I need it same day to ensure my books are on par with what the bank says, but delays happen and there's no controlling little jut's in the system, you just have to get through it. If your wanting conformation, most e-mail client's will show the time stamp of the mail sent in the senders sent folder, ask to see that and if it says Wednesady she's an honest person, she's not trying to get away with not getting you the important document that day… The e-mail client does not change their time stamps by the iPhone time…