Well, the structure of "I believe" doesn't allow for too much story telling so I decided on a kind of generic approach. I mentioned the Beatles' "Yesterday" the other day. There are similarities. In "Yesterday" what would be expected of the chorus - delivering the main message of the song - is presented straight away, nothing much to be done in the way of preparation. Therefore, the story "before" is reduced to a) "I said something wrong" and b) "she has gone", that's it.
After presenting the central idea of "I believe" in the first part - "I believe in our love, let's give it a second chance" - there are only a few lines for delivering what had happened before to provoke that response. I even went a little farther than the Beatles by even leaving it open, who exactly did something wrong. You can read it either way: "you" may have done something wrong and "I" am willing to forgive although you don't seem to be quite convinced; or "I" am to blame and ask "you" to give us another go. The word "escapade" suggests that one has cheated on the other, but I don't explicate who cheated on who. Thus, more people can actually relate to the song reading their own interpretation into it. And I have gained space to "hammer in" my message in the "C" parts: "let's try again".
As for rhyming I consulted RhymeZone yet again. I experimented with lines like "consequences - can be taken or disregarded" but gave up, it didn't match exactly with the meter, and there are hardly any rhymes. "harder" is also hard to rhyme, but I found "ardour" (or "ardor", if you prefer the US spelling) which provoked a rather nice idea: "eventually we'll create new ardour". And the last line has got quite poetic: "let us lay down our armour", that is "let us lay down our arms" re-phrased. Nice, isn't it? Not the perfect rhyme but very nice indeed, I'd say.
This is the complete text:
whatwever we have done and said
I believe in our love
I believe in our love
I believe we can go on
I beg you try to understand
I won't leave you because of that
I won't leave you because of that
I won't leave you for anyone
it's not too late
not each wrong word is meant deviously
an escapade
need not be taken seriously
I know it can be hard
to straighten out the wrong
but bearing grudges may come even harder
whatwever we have done and said
I believe in our love
I believe in our love
I won't leave you for anyone
one mistake
need not taint you eternally
an escapade
need not be taken seriously
I know it can be hard
to straighten out the wrong
but bearing grudges may come even harder
trying to forgive
tryin' to get along
in the long run may be leading farther
a new lease of our love
take the second chance
eventually we'll create new ardour
I believe in our love
I believe in faith and trust
so, let us lay down our armour