Correct

苦苦

/ kǔkǔ / 
Strokes

Definition

strenuously/persistently/hard/painful

Example

As an Adverb

strenuously; hard; persistently

1
Kǔkǔ
苦苦
zhuīqiú
追求

pursue persistently; try hard to get

2
Kǔkǔ
苦苦
sīsuǒ
思索

think/ponder hard; rack one's brains

3
Kǔkǔ
苦苦
āiqiú
哀求

entreat piteously; implore urgently