I'm having trouble finding a good idiomatic German phrase for "I suppose that...", "I imagine that...", "I guess that..." as the typical start of a statement that is intended to soften it somehow. If you consult a dictionary you get sichDat vorstellen and annehmen for "imagine" and "suppose", but I've only ever used sichDat vorstellen in its more literal sense of "conjuring up an image in my mind", and annehmen sounds more like "assuming a fact as true" than "supposing something might be true".
"These have been difficult days, but I imagine they'll be just vague memories in a couple of months."
"She's unprepared but determined. I suppose she'll do fine if she trusts her instincts."
"They tell me he's very angry, so I guess he won't be coming to visit anytime soon."
Is it OK to employ either one of these verbs for my meaning, or is it just not done in German? If the latter, is there any way to translate that idea more idiomatically?