This poem is no walk in the park, that's for sure. While Sidney is very kind when it comes to word choice (no super-weird words that nobody really uses, for example), his sentences are tricky—sinewy, serpentine, complex. The whole bit about "Sure, that long with love acquainted eyes," really threw us for a loop, and we're supposed to be the experts. A couple other sentences in this poem are tricky, but besides those, Sidney isn't totally unreadable. If you want to make your life difficult, however, take a look at some of his other sonnets. They can be pretty tough.