Ok. Last clue;

Ondan doğruyu [gerçeği] söyle........   beklerdim.

söylemişti?

 Deli, what we need is ;

Verb stem [söyle] + Verbal noun + possesive 3 + n [buffering letter] + accusative

so try this way..

nope its scared me off now with the grammar leave it to the clevers

 Psssst... deli: try söylemesini .. or söylemesine (I always get the last ending wrong unless I check the dictionary in this site) but don´t let tunci see we are working together.

Dictionary confirms it is -i beklemek

Not fair! I demand a recount!   Awwwwww .....

I knew it, but you awarded the chocolates to Abla too early. I think she is your favourite!!

Tunci .... you only allowed 40 mins before you awarded the prize! Maybe some of the rest of us weren´t on site to try!!!

Sulking

  You are great, Mazzer !!

Afiyet olsun !

  Thanks Marionin but this just shows me that I really need to go right back to the start and try to study grammar, because unless I do, I will never get to where I want to be

 Dont worry Deli, you are much more clever than many others.

when it comes to grammar, yes grammar is important but there are many people who speak good Turkish with very limited grammar knowledge. And I know some people who speak almost perfect English with very less grammar knowledge..So its sometimes all about practice issue.

And the final form of the sentence is ;

" I would have expected her to tell the truth "

Ondan gerçeği [doğruyu] söylemesini beklerdim.

O [she] + n [buffering n] + dan [ablative] + gerçek [truth, "k" changes into "ğ" ] + i [accusative] + söyle [stem] + me [ suffix that makes verbal noun ] + si [possesive for 3.person] + n [buffering n ]+ i [accusative] + bekle [stem] + r [aorist tense] + di [past] + m [person "I"].

 And this chocolate goes to dear Deli for her great efforts on this complicated sentence.

  Afiyet olsun !