FEOMOS Total Blackout Window Film with Heat Resistant White Side Static Cling 100% Light Blocking Glass Films Cover Room Darkening Romoval 60cm x 200cm

Q: Can you cut this to fit a 44x50 size window?

Depends on what size you ordered

Q: Will this stick to fabric?

It is "non" sticky. It clings to the window

Q: Will this block out heat?

I have this on my south-facing patio doors in Arizona and my answer is: a little bit. You can still feel the heat radiating through the glass and the blackout plastic, but the doors themselves are warm under the same conditions. I'd say the plastic blocks between 5 and 10% of the heat that the bare glass transferred to the room. It doesn't do a lot, but it was inexpensive and easy to install/remove if necessary so I'm happy with it.