I had a thought for no one's but your ears:
That you were beautiful, and that I strove
To love you in the old high way of love;
That it had all seemed happy, and yet we'd grown
As weary-hearted as that hollow moon.
Are they better described thus:
The plainest, most straightforward language in the poem, in some ways, comes at the very end—final words, not uttered in the conversation, are more private and more urgent than what has come before. ... That closing passage of interior thoughts [...] makes the poem feel, to me, as though not simply heard but overheard.
or like this?
... how artificial Yeats's manner of writing was. As a rule, this artificiality is accepted as Irishism, or Yeats is even credited with simplicity because he uses short words, but in fact one seldom comes on six consecutive lines of his verse in which there is not an archaism or an affected turn of speech.