The difference between “宁愿A, 也不B” and “宁愿A, 也要B” is which result is the speaker’s choice.

• 我宁愿不及格，也不考试作弊。
• I would rather fail than cheat in the examination.
• 他们宁愿去钓鱼，也不愿待在家里。
• They would rather go fishing than stay at home.

In “宁愿A, 也不B”, A is the speaker’s final choice.

• 他宁愿花1000块钱，也要买到女朋友最喜欢的礼物。
• In order to buy girlfriend’s favourite present, he would like to spend 1000 yuan.
• 她宁愿自己受伤，也要保护孩子。
• In order to protect the baby, she cares nothing about herself.

In “宁愿A, 也要B”, B is the speaker’s final choice, but the speaker have to complete A to make B to come true.

According to the examples above, we learn that A and B are not all bad cases, which are based on the speaker’s views.