Why will two masses attract each other?

I think the real reason behind this is simply because in our real world, gravity exists as a field thus impacting a form of gravitational pull between two bodies.

You are asking the wrong people. Scientists discover what happens. They make predictions about what will happen in various situations in the future.
Even if somehow we can magically answer the question "why" in terms of OTHER related things, then the question of "why" can be applied to those.
And so ad infinitum.

The only person that actually provides AN answer "God did it" gets a thumbs down for their effort.

WHY questions about physics usually can not be answered. Our science can say what happens but not why it happens.

I have recently learned that matter bends the fabric of space, (also known as 'space-time'). So you are not actually PULLED by
gravity, but you are PUSHED by space-time, due to the way
the matter squinches it up.

Because back in the early moments of our universe, matter got mass and mass got gravitation
You should probably consider gravitation as a peculiar property of our universe..
I'll let you look up "Higgs Field."

Because if they didn't then life wouldn't exist and you couldn't ask that question.
It's a fundamental force.

Well, that is an interesting question and the answer is: that is the way things work in this universe.

The "why" derives from the very nature of the structure and properties of the universe. Why does the universe have this structure and properties and not some other ones? Lots of places one can go with that thinking. Most other alternative possible conditions do not allow for the existence of life as we know it (the universe would be so "alien" to us), so we can only question the nature of the universe here where things are the way they are, because we wouldn't be in a universe that is different.

Let's project space.time onto a flat 2D coordinate system. The grid lines are orthogonal and straight. And they are equidistant and parallel in the horizontal and vertical directions.

Now let's send a massless photon on its way horizontally across the 2D system. Because there is nothing acting on that photon and photons have momentum, that speck of light simply zips by in a straight path from, say, left to right. Why? Because it is following the curvature of our 2D space.time. And that curve doesn't curve, it's straight.

But now let's add a bit of mass.energy at the origin of our 2D projection. According to the general theory of relativity, which has been validated multiple ways, the grid lines, space.time itself, will curve inward toward that bit of mass. In fact, those grid lines compact inward towards that mass from all around that mass.

And the grid lines are no longer equidistant from each other. In fact as we draw closer and closer to that mote of mass, the grid lines smash down tighter and tighter to each other.

What does this have to do with the attraction two masses feel for each other? Just everything, that's what. Let's see how by adding a second mass m to the first one M. m is some distance up above M on our 2D reference frame.

Now our 2D reference frame is compacted around two sites, which are at the M and m locations. So let's allow m to move so that it passes by the static mass M.

Mass m wants to follow a straight line because of its inertia. Turns out that those grid lines are made up of incremental geodesic lines that appear straight to moving bodies. So in moving along a series of geodesic lines, a body will actually follow the curve that those straight lines sum up to make.

Thus following a curved space line, m is "pulled" towards M simply because space is curved inward towards mass M. In fact, because the space is also compacted around m, a similar pull also comes from the moving mass. In other words they are mutually attracted to each other. So there's one characteristic of the gravity picture...mutual attraction and that stems from curved space.time.

Acceleration is the second characteristic. M and m will not only draw closer, they will speed up relative to each other while coming closer. For that we turn again to the 2D projection of ordinary space.time.

When the grid lines are all straight and equidistant, we can declare that such a flat space has zero potential energy. This is not a new model. Physics has used this to define escape velocity for example. To find escape velocity we say that the kinetic energy of a projectile is totally spent when its potential energy is at its maximum value. And to make the escape velocity solution easier we simply set that PEmax = 0.

As that happens in flat space, it means whenever space is curved, the potential energy is PE < 0 some negative value...less than zero. And the more curved that space is the more negative is the potential energy at that point. And there we are. As that mass m follows the compacted curved space inward towards M it loses potential energy. Why? Because as it progresses space becomes more and more warped so potential energy become more and more negative.

And what did we learn about the conservation of total energy? As a body loses PE that energy is converted into kinetic energy to keep the total energy constant. In other words our mass m will pick up speed. It will accelerate as it is drawn in closer to M.

And there we have it. Both attraction and acceleration, the two main characteristics of the pull of gravity. And the curve of space.time is the culprit.

It is gravity

Masses float inside space structure .Gravity is basically the substance of space that holds all atomic structure together.That mysterious substance was, according to Classical physicists , called the Aether. .
Today they call it space time which does not describe any mechanical sense what soever.

Repulsion is something that indicates another Field besides Gravity field.

Actually because the Universe has a space substance boundary with restrains is the cause of gravity. and motion all all celestial bodies and massive particles of light

Einstein Field equation of General relativity relates a Universal Force to a local force in terms of curvatures that surrounds the volume of mass structures.

As per Ralph Rene the cause of repulsion is caused by interaction of massive particles and charges in the configuration of space.

Mass is a structure which most of its volume is space structure. Mass is not energy.Most physicist are not able to define energy.Basically when a mass is in motion it is said to have Energy

Higgs field.

https://physics.aps.org/articles/v6/111

We call it GRAVITY-----but the real explanation is a bit abstract---Einstein showed TIME was part of it. TIME, could be described as A constant Motion in the direction of the 4th dimension that is INHERENT in all matter. So everything is moving in more or less the same direction and the same speed-----But we do not notice this motion in our 3D awareness.---Like cars matching speed, side by side, on a highway, (or articles "sitting still" inside the car) we see no relative motion as all the cars may be moving at 60mph.----But if one veers off, at the same speed towards an exit we then see some relative motion (relative speed will be much less than the 60mph, even though all the vehicles are STILL doing 60)

MASS causes a 4D curvature in space time---Indeed that's what mass IS, each particle being a "dimple in Space time" a large mass will be a significant curve in space time---But we will not notice it in our 3D context. To us, everything may be still, we do not see the 4D speed or curvature. Time continues to move however, but takes a CURVE in direction when space itself curves---So we in our 3D universe feel a "pull" not unlike we feel when we quickly turn a car (inertia), This force we feel seems like an "attraction" to a large near by Mass----the curve and the movement through time, however is hidden from us as we cant sense the 4th dimension---but we DO feel the FORCE of the turn in out 3D world and call it GRAVITY.----so large masses appear to attract each other from our POV.

Gravity is the answer.
Gravity sucks

God designed it this way.