The mermaid’s suitor

Once there was a beautiful mermaid
Whose admirers queued around the equator
A chancer approached from the south
Hoping to win her hand:
‘Mermaid!’, he said, ‘Will you be mine?’
I shall be yours, she replied
If you can answer this one question
‘I am ready!’, said he
How should I recognise a truth?
The chancer thought, then he said:
‘A truth is always a truth
However you look at it
Just as this diamond is always a diamond
However you glimpse its glances.’
The mermaid replied:
Small keys opens large rooms
I am yours
For I am your heart!
And the suitor saw
That her answer indeed was his.