A step-up transformer that makes 220V 60Hz from 110V 60Hz should make the monitor work as intended. The mains frequency is probably not going to cause any problems because internally the monitor will make DC out of the mains AC anyway. That shouldn't be a problem.
However: a European PAL monitor may not be able to show an NTSC (USA) composite video signal. NTSC is 29.97 frames per second and PAL is 25 frames per second; the line frequencies are also different between the two standards. If you feed an NTSC signal to a PAL-only monitor, it may be possible to get the picture steady (sync), but you may see a black-and-white picture unless you use an RGB signal going to the SCART connector. If you're very unlucky, you won't be able to get the video to sync at all but it may be possible to tweak the V-hold control (if it has one) to sync to an NTSC composite signal. Either way, you won't damage the VIC or the monitor by connecting the video signal, even if the monitor can't handle it.
When I was still in the Netherlands, I owned a Philips CM8833 monitor that had both a SCART (RGB and PAL-composite) input and an RGBI input (digital RGB + brightness from a CGA video adapter of an IBM PC), and it worked great at 25 as well as 29.97 or 30 fps (CGA is 30fps). But I'm pretty sure it was unable to decode NTSC, though I never tried.
If you can post the brand and type of the monitor, maybe we can post more accurate answers.
===Jac