I wanted help in determining between the distance between 2 points. It can be by either RF/Bluetooth or anything commercially available.
You can't do it by any kind of RF (BT is radio as well), as lots of ambient factors influence the propagation speed.
For line of sight, Bosch makes awsome LASER "tape measure" units. They're not exactly cheap, but very precise (like max. 5mm deviation in 40m)
With RF, you could however triangulate a single transmitter, using 3 receivers in a delta formation, some distance apart. You'd need to compare the phase of the received signals to find the "time difference" (to find the approximate angle and distance), but you'd need the distance between the receiving antennas to be a few percent less than a wavelength and while easy at high frequencies (which is harder to work with), using a sensible frequency like say 30MHz, they'd have to be almost 10m apart.
Cutting to the bone, it's a case of; if you have to ask, you probably don't have the experience it'll take to get a working solution. Measuring, comparing and storing phase timing is not for beginners.
The 30MHz signal quantized into just a rough measure of 100 possible steps, gives you 333ps/step, so takes super fast electronics to handle (no microcontroller can handle this) and even the PCB layout will have a huge influence, so you really have to know your way around it.
Both the objects may have obstacles like walls/chairs in between and distance & direction are to be measured, The distance may not be exact but slight variation would do.
"slight variation"? (We work with numbers
Except for triangulating an RF signal, nothing would work through a wall.