The Messenger of Allah ﷺ said, "When one of you proposes to a woman, there is no blame upon him if he looks at her, provided he is looking at her only for the purpose of his proposal, even if she is unaware."
حدثنا حسن بن موسى حدثنا زهير عن عبد الله بن عيسى عن موسى بن عبد الله
قال رسول الله ﷺ إذا خطب أحدكم امرأة فلا جناح عليه أن ينظر إليها إذا كان إنما ينظر إليها لخطبته وإن كانت لا تعلم
Its isnad is sahih. Abdullah bin Isa is the son of Abdul-Rahman bin Abu Layla, and he is trustworthy, his hadith appearing in the collections of all the major compilers. Musa bin Abdullah is the son of Yazid al-Khatmi, and he is trustworthy, his hadith appearing in Muslim. This hadith has already appeared in similar form at 14521.