Okay, getting clearer!

[34836] Iª-IIae q. 31 a. 1 co. Respondeo dicendum quod motus appetitus sensitivi proprie passio nominatur, sicut supra dictum est. Affectio autem quaecumque ex apprehensione sensitiva procedens, est motus appetitus sensitivi. Hoc autem necesse est competere delectationi. Nam, sicut philosophus dicit in I Rhetoric., delectatio est quidam motus animae, et constitutio simul tota et sensibilis in naturam existentem. Ad cuius intellectum, considerandum est quod, sicut contingit in rebus naturalibus aliqua consequi suas perfectiones naturales, ita hoc contingit in animalibus. Et quamvis moveri ad perfectionem non sit totum simul, tamen consequi naturalem perfectionem est totum simul. Haec autem est differentia inter animalia et alias res naturales, quod aliae res naturales, quando constituuntur in id quod convenit eis secundum naturam, hoc non sentiunt, sed animalia hoc sentiunt. Et ex isto sensu causatur quidam motus animae in appetitu sensitivo, et iste motus est delectatio. Per hoc ergo quod dicitur quod delectatio est motus animae, ponitur in genere. Per hoc autem quod dicitur constitutio in existentem naturam, idest in id quod existit in natura rei, ponitur causa delectationis, scilicet praesentia connaturalis boni. Per hoc autem quod dicitur simul tota, ostendit quod constitutio non debet accipi prout est in constitui, sed prout est in constitutum esse, quasi in termino motus, non enim delectatio est generatio, ut Plato posuit, sed magis consistit in factum esse, ut dicitur in VII Ethic. Per hoc autem quod dicitur sensibilis, excluduntur perfectiones rerum insensibilium, in quibus non est delectatio. Sic ergo patet quod, cum delectatio sit motus in appetitu animali consequens apprehensionem sensus, delectatio est passio animae.

When you look at the objections they're really interesting:

Articulus 1
[34832] Iª-IIae q. 31 a. 1 arg. 1 Ad primum sic proceditur. Videtur quod delectatio non sit passio. Damascenus enim, in II libro, distinguit operationem a passione, dicens quod operatio est motus qui est secundum naturam, passio vero est motus contra naturam. Sed delectatio est operatio, ut philosophus dicit, in VII et X Ethic. Ergo delectatio non est passio.

Delight is an operation - not a passion - doesn't fall into that kind of experience!!!!

[34833] Iª-IIae q. 31 a. 1 arg. 2 Praeterea, pati est moveri, ut dicitur in III Physic. Sed delectatio non consistit in moveri, sed in motum esse, causatur enim delectatio ex bono iam adepto. Ergo delectatio non est passio.
Delight is not "to be moved" but "in the (completed) moved (motum) - the good that is already secured. (PASSION A MOVEMENT - will have to read response carefully)

[34834] Iª-IIae q. 31 a. 1 arg. 3 Praeterea, delectatio consistit in quadam perfectione delectati, perficit enim operationem, ut dicitur in X Ethic. Sed perfici non est pati vel alterari, ut dicitur in VII Physic. et in II de anima. Ergo delectatio non est passio.

perfection - explicitly brought in - not t suffer or to be altered (VII Physics and II De ANIMA - AHA! Here are the sources - (albeit a little general)! I might need this for the earlier part - for a footnote in asking why Aquinas should put passio and perfectio on a continuum)

[34835] Iª-IIae q. 31 a. 1 s. c. Sed contra est quod Augustinus, in IX et XIV de Civ. Dei, ponit delectationem, sive gaudium vel laetitiam, inter alias passiones animae.

______replies_________

Ad primum ergo dicendum quod operatio connaturalis non impedita, est perfectio secunda (a second perfection - unhindered operation) , ut habetur in II de anima. Et ideo, quando constituitur res in propria operatione connaturali et non impedita, sequitur delectatio, quae consistit in perfectum esse (delight consists in the "to be in the perfected") , ut dictum est. Sic ergo cum dicitur quod delectatio est operatio, non est praedicatio per essentiam, sed per causam.
[34838] Iª-IIae q. 31 a. 1 ad 2 Ad secundum dicendum quod in animali duplex motus considerari potest, unus secundum intentionem finis, qui pertinet ad appetitum, alius secundum executionem, (AHA! HERE IS THE INTENTIO/EXECUTIO dichotomy - I was wondering if "INTENTIO/CONSECUTIO" was as uncustomary as I thought) qui pertinet ad exteriorem operationem (I HAVE TO DISTINGUISH BETWEEN THE TWO! - fix up the first paragraph I wrote - is there a distinction between intention and consecution in passion? Well "consecution" is what makes it difficult - licet ergo in eo qui iam consecutus est bonum in quo delectatur, cesset motus executionis, quo tenditur ad finem; non tamen cessat motus appetitivae partis, quae, sicut prius desiderabat non habitum, ita postea delectatur in habito. Licet enim delectatio sit quies quaedam appetitus, considerata praesentia boni delectantis, quod appetitui satisfacit; tamen adhuc remanet immutatio appetitus ab appetibili, ratione cuius delectatio motus quidam est.
[34839] Iª-IIae q. 31 a. 1 ad 3 Ad tertium dicendum quod, quamvis nomen passionis magis proprie conveniat passionibus corruptivis et in malum tendentibus, sicut sunt aegritudines corporales, et tristitia et timor in anima; tamen etiam in bonum ordinantur aliquae passiones, ut supra dictum est. Et secundum hoc delectatio dicitur passio.

Reply to Objection 2. A twofold movement is to be observed in an animal: one, according to the intention of the end, and this belongs to the appetite; the other, according to the execution, and this belongs to the external operation. (The external operation is quite distinct from the phenomenon of the passion itself - which has its own order that corresponds or motivates the external operation - which ext. op. syncs with the passion as being moved by it - and which passion is in turn moved by the object - and also - insofar as it is free, by freedom, but what is freedom but also a kind of passivity, as we can see from the previous blog - 28.6) And so, although in him who has already gained the good in which he delights, the movement of execution ceases, by which the tends to the end; yet the movement of the appetitive faculty does not cease, since, just as before it desired that which it had not, so afterwards does it delight in that which is possesses. For though delight is a certain repose of the appetite, if we consider the presence of the pleasurable good that satisfies the appetite, nevertheless there remains the impression made on the appetite by its object, by reason of which delight is a kind of movement.