Conditions for Guaranteed Rebirth in the Land of Bliss

The Buddha gave sentient beings only three guarantees for rebirth in the land of bliss (sukhāvatī), all found in the Contemplation Sūtra on Amitāyus. The first: the third of the sixteen contemplations — when the water contemplation is accomplished, it guarantees rebirth in the land of bliss at the end of life. The subsequent fourth through sixteenth contemplations likewise guarantee rebirth in the land of bliss at the end of life, and these count together with the third as one. The second: a person who has eradicated the view of self (satkāya-dṛṣṭi-prahāṇa) is guaranteed rebirth in the land of bliss at the end of life, in the highest grade of the middle tier. The third: a person who has seen the mind is guaranteed rebirth in the land of bliss at the end of life, in the highest grade of the highest tier. Other practice methods can also lead to rebirth in the land of bliss, but they are not guaranteed and are uncertain — one may be reborn there, or one may not, depending on the circumstances of one's final breath.

Why don't the Buddha and the noble ones use supernatural powers to forcibly take sentient beings away?

The Buddha is the Buddha within the mind; the noble ones are the noble ones within the mind. When there is a Buddha in the mind, the Buddha appears; when there are noble ones in the mind, the noble ones manifest. If there is no Buddha or noble one in the mind, and the Buddha and noble ones do not appear, blame your own mind.