Astrid married Harald primarily because she was kidnapped and coerced into the union by King Harald and his men. This was not a consensual marriage but a forced act.
Following her abduction, Astrid was compelled to become Harald's wife, a strategic move that solidified her position as the Queen of the Kingdom of Vestfold-Rogaland. This non-consensual marriage served Harald's ambitions, allowing him to expand his influence and legitimate his claim over territories by forcibly integrating a significant figure into his royal lineage. The marriage was a clear demonstration of Harald's ruthless tactics in consolidating power and expanding his dominion.