Tell Me That It Isn't True Lyrics
They say that you're planning to put me down
All I'd like you to do is tell me that it isn't true
That he's tall, dark and handsome, and you're holding his hand
Darling, I'm a-counting on you
Tell me that it isn't true
It hurts me all over
It doesn't seem right
I don't want to believe them
All I want is your word
So darling, you better come through
Tell me that it isn't true

Why can it not just mean that, he have heard from other people that she is planning to leave him ?

A lovely song ruined by Dylan's, for once, clumsy lyrics. Look at the first two lines: "I have heard rumors all over town They say that you're planning to put me down"
Planning to put me down? It scans and rhymes, but makes no sense. It could only make sense in the following tortuous scenario: Girl having troubles with Bob. She doesn't actually tell anyone where the source of Bob's awfulness lies. She instead tells people that, on a future date yet to be decided, she will divulge why Bob is such a terrible boyfriend. Then these people tell their friends that Bob's girlfriend will, sometime in the near future, tell an expectant township just why Bob is such a terrible boyfriend. This has never happened in the history of human relationships.

It was written about racism during the civil rights movement- The man in the song is dreading that his ex-girlfriend is dating a black man and therefore he will become the ridicule of his racist friends. Read it through now...