From my experience, this matchup is pretty even if mario plays it right. It's vital that mario stays somewhat close to Tink. If he doesn't, he has to deal with projectiles all day. I know he has cape, but let's face it, cape isn't unbeatable, and it leaves Mario vulnerable. Stay close, he can outcamp you.
On the ground, Tink's sword will take priority unless you outspeed him. Mario's fsmash will be able to outspace anything he has though. But to counter this, tink does have that hookshot, and it's annoying when he uses it well, since it beats shielding. Mario can't sit in his shield. Zair is annoying as well, but shielding that isn't too dangerous, and if you stay close, it won't be a major problem.
They're pretty even in the air. Tink doesn't really have a counter to Mario's bair (except his, but it has less range I believe). Mario will get ouright beaten by the sword if he doesn't space well though.
Mario and Tink will kill at about the same percents. Gimping Tink isn't impossible, but it's probably not too reliable.
50/50 (most likely) or 55/45 Tink, only because of mario's extra spacing work because of the sword.