Jansenius and Bellarmine read Trent's canon narrowly; the dispute is verbal
Thesis LV. On Jansenius's reading, the Council of Trent does not define that good works are done before faith, but only before justification. It pronounces anathema not on anyone who says that all works done before faith are sins, but only on anyone who says that everything done before justification is sin. Bellarmine himself explains the canon in just this way.
'The Council does not define,' he says, 'that the works of unbelievers are not sins, but that not all works that precede justification are sins. Even the works done by believers after they have fallen into sin precede justification. For the Council does not follow Luther's rules, who held that faith is lost through every mortal sin, but the Lord's rules, who in Luke 18 approved the prayer of the tax collector, who prayed in faith for the forgiveness of sins.
Nor does the same Council define that the works of sinning believers are not sins without qualification; it added "done in whatever way". So we are to understand that the Council defines only that certain works of sinning believers are not sins, namely those done with God's special help. Only about these did the Council properly mean to define anything, since its purpose was to treat of justification and of the works that dispose to it. And, as the same Council holds, only those works dispose to justification that take their beginning from God's prevenient grace' (On grace and free choice, book 5, chapter 4).
From all this we may conclude that the dispute between the Protestants, who deny, and Jansenius, who affirms, that certain good works are done before justification is only about words. Indeed the same holds between the Protestants and the canon of Trent so often cited, as Jansenius and Bellarmine explain it.
Latin
LV. Ex sensu vero Jansenii Synodus Tridentina non definit bona opera fieri ante fidem, sed solum fieri ante justificationem, & anathema non dicit illi qui dixerit opera omnia quae fiunt ante fidem esse peccata, sed tantum illi qui dixerit peccata esse omnia quae fiunt ante justificationem. Nec aliter ipse Bellarminus exponit Canonem Synodi Tridentinae. Neque definit, inquit, Concilium opera infidelium non esse peccata, sed non esse peccata omnia opera, quae justificationem praecedunt. Praecedunt enim justificationem, etiam illa opera quae fiunt a fidelibus, posteaquam in peccatum ceciderunt. Non enim Concilium sequitur regulas Lutheri, qui per omne peccatum mortale voluit fidem amitti: sed regulas Domini, qui Luc. 18. probavit orationem publicani, qui cum fide oravit pro remissione peccatorum. Neque definit idem Concilium, opera fidelium peccatorum absolute non esse peccata, sed addidit, quocunque modo facta. Ut intelligeremus definiri solum a Concilio, quaedam opera fidelium peccatorum non esse peccata, illa videlicet, quae fiunt cum auxilio speciali Dei. De his enim solis proprie Concilium definire voluit, quoniam propositum illi erat agere de justificatione, & iis operibus, quae ad justificationem disponunt: illa vero sola opera ad justificationem disponunt, ut in eodem Concilio habetur, quae initium sumunt a gratia Dei excitante. De Gratia & libero Arbitrio lib. 5. cap. 4. Ex quibus omnibus concludere licet verbalem solum esse contentionem inter Protestantes dum negant, & Jansenium, dum affirmat Bona quaedam opera fieri ante justificationem: imo inter Protestantes, & saepius citatum Canonem Tridentinum, prout illum Jansenius & Bellarminus exponunt.