I’m currently trying to learn Dutch (yeah, non-professional way with a smartphone app 
), and I think it is relatively easy for me, as a native German speaker. I think the grammar is actually pretty similar - good for me, I’m terrible at learning grammar - and lots of words have at least some resemblance. Still, it is a language of its own and not some “dialect” of German or such… one could as well say that German is a dialect of Dutch 
The second language I’m currently learning is Icelandic - the most unchanged nordic language of all, as far as I know, and that’s really hard for me. Grammar is so different from what I know, and if you think Dutch has some funny-sounding consonants, there is a lot more of that in Icelandic