Here's a poetry site with the poems of Kavanagh:

http://www.poemhunter.com/p/m/poem.asp?poet=6773&poem=30540

Obviously it's "the true worth of passion's pledge" - it's pretty meaningless otherwise! Kavanagh is talking about the worth of the promise of love made by a man to a woman.

And the "words and tint" bit - again, it's obvious; maybe this is just that English is spoken precisely in Ireland, but it seems blindingly obvious to me that Kavanagh is talking about the artists in different media: stone and words and sound and colour; he's talking about the artist's dedication to the gods of the arts.

Here are the words of the poem, as Patrick Kavanagh wrote them:

On Raglan Road
        
On Raglan Road on an autumn day I met her first and knew
That her dark hair would weave a snare that I might one day rue;
I saw the danger, yet I walked along the enchanted way,
And I said, let grief be a fallen leaf at the dawning of the day.

On Grafton Street in November we tripped lightly along the ledge
Of the deep ravine where can be seen the worth of passion's pledge,
The Queen of Hearts still making tarts and I not making hay -
O I loved too much and by such and such is happiness thrown away.

I gave her gifts of the mind I gave her the secret sign that's known
To the artists who have known the true gods of sound and stone
And word and tint. I did not stint for I gave her poems to say.
With her own name there and her own dark hair like clouds over fields of May

On a quiet street where old ghosts meet I see her walking now
Away from me so hurriedly my reason must allow
That I had wooed not as I should a creature made of clay -
When the angel woos the clay he'd lose his wings at the dawn of day.

Patrick Kavanagh