We do not easily think ill of those whom we love most, and the taint of suspicion cannot exist along with warm affection.

[Non enim facile de his quos plurimum diligimus turpitudinem suspicamur, nec in vehementi dilectione turpis suspitionis labes potest inesse.]

Peter Abelard (1079-1142) French philosopher, theologian, logician [Pierre Abélard]

Historia Calamitatum Mearum [The Story of My Misfortunes], ch. 6 (1132) [tr. Radice (1974)]
    (Source)

On how Heloise' uncle, Fulbert, had no suspicion of her romantic relationship with Abelard.

(Source (Latin)). Alternate translation:

Indeed we do not easily suspect shame in those whom we most cherish, nor can there be the blot of foul suspicion on devoted love.
[tr. Bellows (1922)]

The first half of the sentence is most commonly quoted. Other variants include:

• "For it is not easy to suspect vileness in those whom we love most."
• "For we do not easily expect evil of those whom we love most."