Wind resistance is the major factor when towing a trailer at speed. Given your trailer is open and about same width of the car, drag won't be increased that much.

Will it be hilly where you are traveling, at what speed and for how long?

Does the trailer have brakes? 1,500 - 2,000 Lb is the typical limit for a non braked trailer to be legal. While less of an issue with a rear drive car, the rear of a front drive car can be pushed around under hard braking especially if you are braking hard and turning to avoid something. Trailer brakes reduce this effect dramatically.

Under braking, the cars nose drops and tail rises. This lifts the trailer tongue up transferring weight off the tongue and to the trailer axle further reducing the cars rear loading.

There is also a sway issue with long single axle trailers that can be recovered from by applying the trailer brake to straighten out the whole train. Yours is short so not a big deal but still a nice feature to have.

In general, most anything can tow most anything else, it just depends on how fast / how far and how safe you want to be. In your case, the MB will not have a problem going or stopping, I'd be more concerned about the Jetta stopping and being stable.