nierealne in English:

She had rather unrealistic expectations of marriage.

He is unrealistic.

Life on a desert island. Most of us have formed an unrealistic picture of life on a desert island. We sometimes imagine a desert island to be a sort of paradise where the sun always shines. Life there is simple and good.

She has a totally unrealistic view of life. [+ to do sth] It's unrealistic to expect their decision before Tuesday.

Parents look to the new generation as a generation that is far from reality and busy running after unrealistic dreams.

The feelings of "love at first sight" and "faithful unto death" are unrealistic; this sort of unrealistic and illusory feeling is not what we need.