In the sentence
SHE SAID SHE LOVES HIM
there are six locations for "only" (and a few for "also") and each location varies the meaning because these words modify the word they are nearest to.
Only she said she loves him
- she is the only one who said this
She only said she loves him
- she is the only one who said so
- she only SAID it, but did not believe it
(Which meaning depends on which word "only" is modifying)
- what she did was trivial -- only a speech act
(in spoken English, it would be rare to misunderstand the speaker's meaning)
She said only she loves him
- she claimed to be the sole person who loves him
(But: She said only that she loved him = she said no more than one thing -- that she loved him, and did not add anything else)
She said she only loves him
- but does not "like" him
- This could also be taken to mean "she said she was the sole person to love him"
She said she loves only him
- she said he was the only one she loves
She said she loves him ONLY
- she said he was the only one she loves