Give it 2~3 hours in, if by then I'm not feeling it, I'll probably not gonna finish it unless I have hope it gets better.
But then again you're talking to someone who beat Family Guy something something Multiverse because he was bored, don't take my word for it. Sometimes you just want to see that trainwreck in person. And I've been pretty vocal about how much I dislike a LOT of things about Xenoblade 2, still somehow was able to finish it AND get all the non new game + gacha BLADEs, even though I was pretty much feeling off about the whole thing more often than not, it was Xenoblade, I paid full price, I had to see it through.
So, money spent is actually a very good motivator, somehow I've beaten every 3DS physical retail game I've bought besides Mario Kart 7, and that's counting Paper Mario Sticker Star! AND THAT GAME... Is certainly something I've been warned about. But hey sometimes you got to press on if you ever intend to finish a game, you'll be at least able to say "Yes, I can talk about that one, I've played it to the end, dammit!", and it was like 50% off, surely it couldn't be thaaat bad, right?... Hahaha, ha. (If you have a 3DS, the best Mario RPGs are probably the remakes for Bowser's Inside Story/Superstar Saga, just, just go get those instead, please)