In a word, betray TA: find out who TA said sweet words to.
Slide to the right on the iPhone homepage, and the system comes with a search box, which is very easy to use. Enter keywords directly, for example, I love you, about? By analogy, iPhone will automatically search out all relevant items in Weibo, SMS and memo, and some contents may be visible even if deleted.
There is also a search box at the top of the main page of WeChat chat. You can also query related chat records by entering keywords. Of course, the premise is that TA has not deleted the chat record.