Ending a declarative statement with a question mark? [duplicate]

Solution 1:

I assume OP is referring to...

high rising terminal (HRT) - also known as moronic interrogative, uptalk, upspeak, rising inflection, unnecessary inflection, or high rising intonation (HRI). A feature of some accents of English where statements have a rising intonation pattern in the final syllable or syllables of the utterance.

It doesn't really indicate a question in the mind of the speaker (unless maybe it's a kind of generic "How will you respond to what I just said?", or "Is that okay with you?"). The general principle in English is only write a question mark at the end of a question, which OP's example probably isn't.

I and many other people find it incredibly irritating, but you can't change how people speak. That Wikipedia link above says, it is ridiculed in Britain as "Australian question intonation", but I think Americans also associate it with Southern California Valley Girl speech.