Playing the doubting Thomas*. There are times in meetings or discussions when you can’t/don’t want to remain neutral or ‘sit on the fence’ but you can’t/don’t want to disagree with somebody either. So it’s a kind of in the middle somewhere. Welcome to the realm of ‘doubting’ (and remember the ‘b’ is silent.!)
“I doubt …”
“I have my/some/serious = grave doubts about …”
“to express doubts about“.
Here are some other useful phrases with doubt:
“There is some doubt about it.”
“There is no doubt (whatsoever) that”
“Without a shadow of a doubt”
“To raise doubt about”
“To caste doubt on”
On a more formal level you can always use the words ‘reservation’ or ‘misgiving’
“I have reservations/misgivings about …”
“to express reservations/misgivings about“.
However, it is common to use the “yes, but” principal in discussions, whereby we initially use a more positive sounding starter followed by ‘but’. Here are a couple more to add to your arsenal:
“Yes, but …”
“Up to a point, but ….”
“To a certain point/extent, but …”
* a person who is unlikely to believe something until they see proof of it. It comes from St Thomas in the Bible, who did not believe that Jesus Christ had risen from the dead until he saw and touched his wounds.
to ‘sit on the fence’ (zwischen 2 Stühlen sitzen), initially (zuerst), to be unlikely (unwahrscheinlich), proof (Beweis)