Hi Tenina - not sure of exactly what you want, but if it is something like quince paste - then I would get an apple (Granny Smith) a little on the green side, core, peel and all (except stem) and chop and blitz it (Speed 10) add some water and cook on 70 degrees speed 1 for 10 mins, then blitz again and strain (if necessary). The resultant mush will help set jams, pastes etc. Quince will do the same - but apple would blend into the fennel/pear without overpowering the flavours.
For a fennel/pear paste - are you chopping the fennel and cooking it before adding the pear?
Making quince paste takes so long, that's the only problem - but the TMX stirs it constantly.