Flux Capacitor recently posted a portion of this poem on her blog, and it caught my eye. So I Googled it and tracked it down...
by Thomas Moore
Have you not seen the timid tear
Steal trembling from mine eye?
Have not mark'd the flush of fear,
Or caught the murmur'd sigh?
And can you think my love is chill,
Nor fix'd on you alone?
And can you rend, by doubting still,
A heart so much your own?
To you my soul's affections move
Devoutly, warmly true;
My life has been a task of love,
One long, long thought of you.
If all your tender faith is o'er,
If still my truth you'll try;
Alas! I know but one proof more,--
I'll bless your name and die!