I looked in my heart while the wild swans went over.
And what did I see I had not seen before?
Only a question less or a question more;
Nothing to match the flight of wild birds flying.
Tiresome heart, forever living and dying,
A  rhetorical question   for which there is no answer, and will encapsulate what will follow. She is seeking something beyond the mundane, everyday routine. 
 The speaker repeats the idea of scrutiny — in two lines she uses ‘looked’, ‘see’ and ‘seen’.
Wild Swans