The poem starts with the word 'not', a negative, which is ironic because from the title we expect it to be a love poem and therefore begin positively
Straight away the poem challenges cliche ideas of love and valentines, as Duffy asserts that she is not giving her partner a 'typical' gift
"It promises light"
Despite an onion being a very unconventional gift for a loved one, this line shows that Duffy wants the recipient to understand that it is given with care
Shows how an unlikely gift or thing can still be positive and make someone happy - shows optimism for embarking on a new relationship with someone
"It will blind you with tears / Like a lover "
Duffy returns back to using a more sullen tone, reminding her lover that relationships can and will still hurt you
Simile comparing love and the onion shows that love can sting and make us emotional (onions make people ‘cry’)
"I am trying to be truthful"
Duffy trying to be 'truthful' again shows that expressions of love can come in unconventional ways, it can seem blunt or curt
Love is often something shrouded with expectations and ideals, however this poem exposes the real, sometimes ugly, truth behind real relationships
"Its fierce kiss will stay on your lips,
possessive and faithful"
'possessive' has very negative connotations of control and power, whereas 'faithful'has good connotations of loyalty and truth - both of these being used in the same line to describe this relationship shows the conflicting nature of love and how there are always good and bad traits within a partner
'stay on your lips' shows that love is strong and dominant, and both the good and bad aspects of a relationship will stay with you
"Its scent will cling to your fingers,
cling to your knife"
Duffy mixes harsh, unusual ideas within a poem about valentines, comparing love to the scent of an onion, which is usually seen as a bad, unpleasant thing, however here she is referring to its strength, showing that love is potent and resonates