Solution:
Boron is a non-metal and its electronic configuration is Being a non-metal, it is less interested in losing three ions and forming a cation, However, if the technique of removing electrons is still in-cooperated in boron, then the removal of the outermost electron requires a significant amount of energy due to its tiny size and high effective nuclear charge.
When one electron is removed, then B forms B+ and has a He-like structure. Removal of another electron from B+ is harder than the removal of the previous electron from B because, firstly, B has a positive charge which reinforces the effective nuclear charge on the 2s electrons, and secondly, B+ has an inert electronic configuration like He.
Removal of an electron from B+ forms B2+. After that, the removal of one more electron from the 2s orbital from B2+ to form B3+ is extremely difficult and requires an incredible amount of energy to remove the electron from the 2s orbital of B2+.
This concludes that a tremendous amount of energy is required for the formation of B3+ from B.