Learn Finnish: Pitkä lentoaika ei houkuttele meitä yhtään. - A long flight time does not attract us at all.

There are actually two rules at play here. The most absolute rule is that the sentence is negative (ei houkuttele), which always forces a partitive object. However, even if the sentence were positive, the verb houkutella (to attract, to tempt) inherently takes a partitive object because it expresses an ongoing influence or emotion rather than a completed action.

What is the base form of houkuttele, and how do we get this negative form?

The infinitive is houkutella, which is a Type 3 verb. To form the present tense stem of a Type 3 verb ending in -lla, you replace the -lla with -le-, giving you the stem houkuttele-. In negative sentences, you simply pair the negative verb (ei) with this weak stem without adding any personal endings.

Could I use the verb houkuttaa instead of houkutella in this sentence?

Yes, you could say ei houkuta meitä yhtään, and the meaning would be practically identical. Houkuttaa (Type 1) and houkutella (Type 3) both mean to tempt or to attract. Houkutella is a frequentative verb and can sometimes carry a slightly more active or continuous nuance (like coaxing), whereas houkuttaa just describes the general feeling of appeal, but native speakers use them interchangeably here.

Can yhtään be used in positive sentences too?