オランダ語の「kijk maar」はどういう意味？

The pattern is the same as kom maar: a verb plus the maar particle, where maar downgrades the verb from order to invitation. Kijk maar (literally "look just") tells someone to take a look without pressure.

The phrase's pragmatic specialization is demonstration. A Dutch teacher pointing to the whiteboard, a Dutch parent showing a kid a recipe, a Dutch retailer pointing at a product on the shelf will all reach for kijk maar. It's the Dutch equivalent of "see for yourself" or "have a look." It also works as mild challenge, in the sense of "look at it yourself and decide" — when someone's skeptical of a claim, kijk maar invites them to verify.

In customer-service contexts, kijk maar is the safer, friendlier alternative to kijk (which would feel too commanding). Service workers say kijk maar dozens of times a day pointing at menus, racks, options, displays.