Why people use the word 'rip' I don't know. Not having a go at you, just confused at how words seem to get redefined. To me you're just 'recording' it. Ripping implies you're taking an exact digital copy of a digital medium. Maybe I'm just old!
However, if you value any of your music on cassette I'd urge you to buy a working cassette deck or repair the one you have. If your current deck is playing slowly I'd also suspect the speed will not be constant. Not only this, but any low frequency bass may disappear due to falling foul of filters in the cassette deck (slowing bass makes it even more bassy, possibly sub-audible) or filters (or perhaps just frequency response) on the input of your soundcard.
Once in the digital domain, resampling shouldn't cause any problems. However, judging the % required may be tricky!
Alec124c41 is correct though, resampling is your friend. You don't want to preserve the current pitch (which is flat) or the tempo (which is slow). You want both increased

Good luck!