How to ask for a repeat in different way politely? [duplicate]

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How do you decide which phrase to use when asking people to repeat what they said?

If I can't understand what someone said very well, how to ask him to repeat his words, but in slightly different way?

If I say, I don't understand, he may think that I'm not agree with his opinion. I'm not sure if Pardon? or Sorry? work in written English.

If what he said looks very simple: there is no uncommon words, then, I am expected to understand, however I can't. So it's more likely that I'm against their opinions if I say I don't understand. Because what he said is so easy. So, I would like him to repeat his sentence in a different way, using different words maybe. How can I ask him to repeat in different way politely?

If I was in your shoes, that is, if I needed a rephrasing to be sure that I understood what the person was trying to say, I'd simply use:

Could you please rephrase that? I'm not sure I understand what you mean.

or,

Would you please rephrase that? I want to make sure I understand you correctly.

The word "rephrase" would be a good clue that the writer should try to make the same point using different words, and the word "please" keeps it all polite.