The thought of walking through fire is an extreme thought. Just as extreme as the feelings this person has for their partner. It puts into perspective how far this person would go to make the other feel their love. 

This person is so consumed with their partner that they can't imagine doing anything else. It proves the idea of the "honeymoon stage" as they see through all of their partners flaws. 

This set of lyrics show just how deep this persons feelings go. They say that they are so infatuated with their partner that the partner doesn't even need to reciprocate the feelings, because their feelings won't change. 

The introduction of this song uses it's lyrics to set up a visual of the persons love affair.  

This is another example of how the speaker views its partner. 
Both of these lyrics include fruits and food which connects this song to Harry's other songs throughout his Fine Line album. 

The speaker uses the imagery of their partners eyes to show the depth of their love. The eyes are the key to the soul, you can't see the soul but you can see they eyes. The usage of this lyric has deep imagery meaning.