redelijk in English:

Tom was reasonably certain that Mary had stolen his grandfather's gold watch.

It's equivalent to being able to hold a reasonably confident basic conversation.

can communicate in English reasonably well

She's doing reasonably well.

The instructions are reasonably straightforward.

The hotel is reasonably comfortable.

We can not reasonably ask more.

It cannot reasonably be assumed that decreasing the dose would reduce the risk of side-effects.

You can reasonably expect her to come.

I have included the names and prices of a couple of hotels which are reasonably close to where I live.

How long does it take to get reasonably skilled?