Learn Swedish: Du måste sudda ut din dåliga gissning.

Sudda alone means to smudge or to use an eraser. Adding the particle ut creates a phrasal verb meaning to erase completely or to rub out, emphasizing the result of making something disappear.

Which word gets the emphasis when speaking the phrase sudda ut?

Because sudda ut is a phrasal verb, the spoken stress always falls heavily on the particle ut, rather than on the verb sudda.

Why does the adjective dåliga end in -a when gissning is a singular word?

After a possessive pronoun like din, adjectives must take the weak declension, which ends in -a. This applies regardless of the noun's gender or whether it is singular or plural.

Since dåliga has the weak/definite ending, why isn't the noun written as gissningen?

In Swedish, a noun following a possessive pronoun must stay in its indefinite form (gissning). The possessive din already makes the noun specific, so adding the definite suffix -en is grammatically incorrect.