Pureland is not as easy. It is unlike promise of heaven. There
are different levels of faith/vow, as well as different levels of
concentration in chanting Amitabha during the moment of death. Upon
rebirth of pureland, there are also many different levels as a
result.
In Master Ou Yi's commentary of Amitabha sutra:
Faith - faith in oneself, faith in sutra/Amitabha Buddha, faith
in cause, faith in consequence, faith in arising of sukavathi,
faith in non-duality (信自, 信他, 信因, 信果, 信事, 信理)
Vow - Vow to leave the Saha World, Vow to be reborn in pureland.
厌离娑婆,欣求极乐
Practise - whole-hearted chanting of Amitabha's name 一心不乱
According to Master Ou Yi, whether to be reborn, depends on
faith/vow ... how high the resultant level, depends on practise
To go to heaven, there is no need to vow to leave Saha
World.
Imagine Sukavathi is at one radio frequency, we need to tune our
thought at the same frequency to receive the signal. If our thought
is tuned in to the Saha World channel ... how to be reborn?