I know there are a lot of individuals dealing with this issue and if you are like me you spend hours searching "how to delete messages in spotlight search history" and it seems like every post either says to reset your phone or sync it! I'm sorry but I did not want to go through the hassle of resetting my phone but I did try to sync it which did nothing so I decided to just mess around with my settings and I believe to have found the answer to everyone's question!!
This worked for me so I really hope this works for you! Just follow the steps below:
1. Go to <settings><general><spotlight search><uncheck messages>
2. Then turn your phone off and wait a minute! Turn your phone back on and off again 2 or 3 more times while waiting a minute in between turning it off!
3. After you are done doing that go back to step 1 and <check messages>!
4. Now go to your spotlight search and those messages should be deleted! If they are deleted I would recommend going back to step 1 and <uncheck messages> so you do not have the same problem with messages showing up again in the spotlight search!
It works for Mail too! Just follow the same steps listed above but uncheck mail instead of messages or do both at the same time!!
*Here is an extra tip which will remove deleted Mail Messages, just follow the steps below:
1. Go to <settings><mail, contacts, calendars><your mail account> scroll down and click <advanced> Now click <remove> under the title Deleted Messages and you can choose to have your mail removed After One Day, After One Week, After One Month or Never.
I hope this post was detailed enough and easy to understand!
I really hope it works for you like it did for me!