2 cables in same conduit
Overstuffed and undergrounded
Your first problem is that a pair of 12/2 UF lines simply won't fit in a ¾&quot; schedule 40 PVC conduit.  Encore Wire's UF specsheet says that their 12/2 cable is 0.195&quot; by 0.415&quot;, or 4.95 by 10.5 mm when converted to metric.  However, NEC Chapter 9 Note 9 says that we need to use the width of the cable as our diameter when computing fill for non-round jacketed cables, which means that one of our 12/2 cables takes up 87.3mm² of fill:

(9) A multiconductor cable, optical fiber cable, or flexible
cord of two or more conductors shall be treated as a
single conductor for calculating percentage conduit or
tubing fill area. For cables that have elliptical cross
sections, the cross-sectional area calculation shall be
based on using the major diameter of the ellipse as a
circle diameter. Assemblies of single insulated conductors without an overall covering shall not be considered
a cable when determining conduit or tubing fill area.
The conduit or tubing fill for the assemblies shall be
calculated based upon the individual conductors.

Given that a Schedule 40 PVC conduit only supples 131mm² of usable fill area at 40% fill, your conduit is quite clearly overstuffed, even if you're permitted to use a 40% fill factor, as pulling two cables thru a conduit might be treated as the same as 2 wires, which forces you to a 31% fill factor instead.
Worse yet, upsizing the conduit won't save you, because the pool pump area itself is considered to be a &quot;corrosive environment&quot; by NEC 680.14(A):

680.14 Corrosive Environment.
(A) General. Areas where pool sanitation chemicals are
stored, as well as areas with circulation pumps, automatic chlorinators, filters, open areas under decks adjacent to or abutting
the pool structure, and similar locations shall be considered to
be a corrosive environment. The air in such areas shall be
considered to be laden with acid, chlorine, and bromine
vapors, or any combination of acid, chlorine, or bromine
vapors, and any liquids or condensation in those areas shall be
considered to be laden with acids, chlorine, and bromine
vapors, or any combination of acid, chlorine, or bromine
vapors.

Assuming this is a permanently installed pool, this then combines with the pool pump motor wiring requirements in NEC 680.21(A)(1) to forbid the use of UF cable, with its bare copper grounding conductor, for wiring in the vicinity of the pump:

680.21 Motors.
(A) Wiring Methods. The wiring to a pool motor shall comply
with (A)(1) unless modified for specific circumstances by
(A)(2), (A)(3), (A)(4), or (A)(5).
(1) General. Wiring methods installed in the corrosive environment described in 680.14 shall comply with 680.14(B) or
shall be type MC cable listed for that location. Wiring methods
installed in these locations shall contain an insulated copper
equipment grounding conductor sized in accordance with
Table 250.122 but not smaller than 12 AWG.
Where installed in noncorrosive environments, branch
circuits shall comply with the general requirements in Chapter 3.

As a result, you're simply better off pulling individual insulated 12AWG THHN conductors (two black hots, two white neutrals, and a green insulated ground) through your conduit.  This handily fits in your ¾&quot; PVC, using up a mere 42.91mm² of fill, and provides the insulated grounding conductor required by the NEC for that corrosive-area situation.